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UCLA Radiology


Research Publications

December 2014

Imaging Techniques in Spinal Cord Injury.

Ellingson BM, Salamon N, Holly LT.

BACKGROUND: Spinal imaging plays a critical role in the diagnosis, treatment, and rehabilitation of patients with spinal cord injury (SCI). In recent years there has been increasing interest in the development of advanced imaging techniques to provide pertinent microstructural and metabolic information that is not provided by conventional modalities. METHODS: This review details the pathophysiological structural changes that accompany SCI, as well as their imaging correlates. The potential clinical applications of novel spinal cord imaging techniques to SCI are presented.

December 2014

Applications of Cardiac CT in the Tetralogy of Fallot Patient.

Lluri G, Aboulhosn JA, Moriarty JM, Finn JP, Ruehm SG, Budoff MJ, Vorobiof G, Yang EH.

In various subsets of tetralogy of Fallot (TOF) patients, the anatomic heterogeneity, myriad of potential surgical palliations, and the potentially associated intracardiac and extracardiac anomalies encountered must be taken into consideration when imaging a patient with TOF. Multidetector cardiac computed tomography (MDCT), with its superior spatial and temporal resolution, has become a valuable modality in evaluating the complex anatomic findings associated with both unrepaired (Figure 1) and repaired TOF patients that traditional echocardiography may have difficulty visualizing or...

December 2014

Size-specific, Scanner-independent Organ Dose Estimates in Contiguous Axial and Helical Head CT Examinations.

McMillan K, Bostani M, Cagnon C, Zankl M, Sepahdari AR, McNitt-Gray M.

PURPOSE: AAPM Task Group 204 introduced size-specific dose estimates for pediatric and adult patients undergoing body CT examinations. This investigation extends that work to head CT exams by using Monte Carlo simulations to develop size-specific, scanner-independent CTDIvol-to-organ-dose conversion coefficients. METHODS: Using eight patient models from the GSF family of voxelized phantoms, dose to the brain and lens of the eye was estimated using Monte Carlo simulations of contiguous axial and helical scans for 64-slice multidetector CT scanners from four major manufacturers. For each patient model and scan mode, scanner-independent CTDIvol-to-organ-dose conversion coefficients were calculated by normalizing organ dose by scanner-specific 16 cm CTDIvol values and averaging across all scanners. Head size was measured using both geometric and attenuation-based size metrics. Head perimeter and effective diameter (ED), both geometric size metrics, were measured directly from the GSF data at the first slice superior to the eyes. Because the GSF models' pixel data are provided in terms of organ identification numbers instead of CT numbers, an indirect estimate of water equivalent diameter (WED), an attenuation-based size metric, was determined based on the relationships between WED and both ED and perimeter for a sample of patient data. Correlations between CTDIvol-to-organ-dose conversion coefficients and the various patient size metrics were then explored.

December 2014

Convex Gradient Optimization for Increased Spatiotemporal Resolution and Improved Accuracy in Phase Contrast MRI.

Middione MJ, Wu HH, Ennis DB.

PURPOSE: To evaluate convex gradient optimization (CVX) for increased spatiotemporal resolution and improved accuracy for phase-contrast MRI (PC-MRI). METHODS: A conventional flow-compensated and flow-encoded (FCFE) PC-MRI sequence was compared with a CVX PC-MRI sequence using numerical simulations, flow phantom experiments, and in vivo experiments. Flow measurements within the ascending aorta, main pulmonary artery, and right/left pulmonary arteries of normal volunteers (N = 10) were acquired at 3T and analyzed using a conventional FCFE sequence and a CVX sequence with either higher spatial resolution or higher temporal resolution. All sequences mitigated chemical shift-induced phase errors and used equivalent breath-hold durations.

December 2014

Primary Angiitis of the Central Nervous System Presenting as Unilateral Optic Neuritis.

Rao NM, Prasad PS, Flippen CC 2nd, Wagner AS, Yim CM, Salamon N, Vinters HV.

A middle-aged woman who experienced recurrent episodes of unilateral vision loss and eye pain. On presentation, magnetic resonance imaging (MRI) demonstrated left optic nerve enhancement with patchy hyperintensities in the white matter of both frontal lobes and ill-defined enhancement in a lenticulostriate distribution. Ophthalmologic examination revealed left optic disc edema with a macular scar consistent with neuroretinitis. Her subsequent clinical course was notable for 2 episodes of painful vision loss, without associated neurologic symptoms, which resolved with intravenous and oral steroids. More than 1 year after her initial presentation, the patient developed right facial weakness and slurred speech, and shortly thereafter suffered a fatal intracerebral hemorrhage. Histopathology on autopsy confirmed a diagnosis of primary angiitis of the central nervous system (PACNS). This is an unusual case of PACNS presenting with recurrent unilateral optic neuritis. The vascular enhancement pattern on MRI suggesting inflamed cerebral blood vessels is a rarely described pattern, which likely reflects intracerebral extension of the ocular pathology. The combination of neuroretinitis and perivascular MRI enhancement pattern may represent a subtype of PACNS.

December 2014

Noncontrast Enhanced Four-dimensional Dynamic MRA with Golden Angle Radial Acquisition and k-space Weighted Image Contrast (KWIC) Reconstruction.

Song HK, Yan L, Smith RX, Xue Y, Rapacchi S, Srinivasan S, Ennis DB, Hu P, Pouratian N, Wang DJ.

PURPOSE: To explore the feasibility of 2D and 3D golden-angle radial acquisition strategies in conjunction with k-space weighted image contrast (KWIC) temporal filtering to achieve noncontrast enhanced dynamic MRA (dMRA) with high spatial resolution, low streaking artifacts and high temporal fidelity. METHODS: Simulations and in vivo examinations in eight normal volunteers and an arteriovenous malformation patient were carried out. Both 2D and 3D golden angle radial sequences, preceded by spin tagging, were used for dMRA of the brain. The radial dMRA data were temporally filtered using the KWIC strategy and compared with matched standard Cartesian techniques.

November 2014

Image-guided Tumor Ablation: Standardization of Terminology and Reporting Criteria-a 10-year Update.

Ahmed M, Solbiati L, Brace CL, Breen DJ, Callstrom MR, Charboneau JW, Chen MH, Choi BI, de Baère T, Dodd GD 3rd, Dupuy DE, Gervais DA, Gianfelice D, Gillams AR, Lee FT Jr, Leen E, Lencioni R, Littrup PJ, Livraghi T, Lu DS, McGahan JP, Meloni MF, Nikolic B, Pereira PL, Liang P, Rhim H, Rose SC, Salem R, Sofocleous CT, Solomon SB, Soulen MC, Tanaka M, Vogl TJ, Wood BJ, Goldberg SN; International Working Group on Image-Guided Tumor Ablation; Interventional Oncology Sans Frontières Expert Panel; Technology Assessment Committee of the Society of Interventional Radiology; Standard of Practice Committee of the Cardiovascular and Interventional Radiological Society of Europe.

Image-guided tumor ablation has become a well-established hallmark of local cancer therapy. The breadth of options available in this growing field increases the need for standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison among treatments that use different technologies, such as chemical (eg, ethanol or acetic acid) ablation, thermal therapies (eg, radiofrequency, laser, microwave, focused ultrasound, and cryoablation) and newer ablative modalities such as irreversible electroporation. This updated consensus document provides a framework that will facilitate the clearest communication among investigators regarding ablative technologies. An appropriate vehicle is proposed for reporting the various aspects of image-guided ablation therapy including classification of therapies, procedure terms, descriptors of imaging guidance, and terminology for imaging and pathologic findings. Methods are addressed for standardizing reporting of technique, follow-up, complications, and clinical results. As noted in the original document from 2003, adherence to the recommendations will improve the precision of communications in this field, leading to more accurate comparison of technologies and results, and ultimately to improved patient outcomes.

November 2014

Cost-effectiveness of CT screening in the National Lung Screening Trial.

Black WC, Gareen IF, Soneji SS, Sicks JD, Keeler EB, Aberle DR, Naeim A, Church TR, Silvestri GA, Gorelick J, Gatsonis C; National Lung Screening Trial Research Team.

BACKGROUND: The National Lung Screening Trial (NLST) showed that screening with low-dose computed tomography (CT) as compared with chest radiography reduced lung-cancer mortality. We examined the cost-effectiveness of screening with low-dose CT in the NLST. METHODS: We estimated mean life-years, quality-adjusted life-years (QALYs), costs per person, and incremental cost-effectiveness ratios (ICERs) for three alternative strategies: screening with low-dose CT, screening with radiography, and no screening. Estimations of life-years were based on the number of observed deaths that occurred during the trial and the projected survival of persons who were alive at the end of the trial. Quality adjustments were derived from a subgroup of participants who were selected to complete quality-of-life surveys. Costs were based on utilization rates and Medicare reimbursements. We also performed analyses of subgroups defined according to age, sex, smoking history, and risk of lung cancer and performed sensitivity analyses based on several assumptions.

November 2014

Toward Clinically Usable CAD for Lung Cancer Screening with Computed Tomography.

Brown MS, Lo P, Goldin JG, Barnoy E, Kim GH, McNitt-Gray MF, Aberle DR.

OBJECTIVES: The purpose of this study was to define clinically appropriate, computer-aided lung nodule detection (CAD) requirements and protocols based on recent screening trials. In the following paper, we describe a CAD evaluation methodology based on a publically available, annotated computed tomography (CT) image data set, and demonstrate the evaluation of a new CAD system with the functionality and performance required for adoption in clinical practice. METHODS: A new automated lung nodule detection and measurement system was developed that incorporates intensity thresholding, a Euclidean Distance Transformation, and segmentation based on watersheds. System performance was evaluated against the Lung Imaging Database Consortium (LIDC) CT reference data set.

November 2014

Diffusion Tensor Imaging Predicts Functional Impairment in Mild-to-moderate Cervical Spondylotic Myelopathy.

Ellingson BM, Salamon N, Grinstead JW, Holly LT.

BACKGROUND CONTEXT: Magnetic resonance imaging (MRI) is the standard imaging modality for the assessment of cervical spinal cord; however, MRI assessment of the spinal cord in cervical spondylotic myelopathy patients has not demonstrated a consistent association with neurologic function or outcome after surgical or medical intervention. Thus, there is a need for sensitive imaging biomarkers that can predict functional impairment in patients with advanced cervical spondylosis. PURPOSE: To implement diffusion tensor imaging (DTI) as an imaging biomarker for microstructural integrity and functional impairment in patients with cervical spondylosis. STUDY DESIGN: Nonrandomized, single institution study. PATIENT SAMPLE: Forty-eight cervical spondylosis patients with or without spinal cord signal change underwent DTI of the spinal cord along with functional assessment. OUTCOME MEASURES: Functional measures of neurologic function via modified Japanese Orthopedic Association (mJOA) score. METHODS: A zoomed-echoplanar imaging technique and two-dimensional spatially selective radiofrequency excitation pulse were used for DTI measurement. Fractional anisotropy (FA), mean diffusivity (MD), radial and axial diffusion (AD) coefficient, AD anisotropy, ψ, defined as AD-MD, and the standard deviation (SD) of primary eigenvector orientation were evaluated at the site of compression.

November 2014

Osteochondral Lesions in Pediatric and Adolescent Patients.

Ghahremani S, Griggs R, Hall T, Motamedi K, Boechat MI.

Osteochondral lesions are acquired, potentially reversible injuries of the subchondral bone with or without associated articular cartilage involvement. Injury results in delamination and potential sequestration of the affected bone. Although an association with mechanical and traumatic factors has been established, the etiology remains poorly understood. These lesions commonly occur in the knee; articular surfaces of the elbow, ankle, hip, and shoulder are also affected. Osteochondral lesions are relatively common in children and adolescents, and the incidence is increasing. Prognosis of these lesions depends on stability, location, and size of the lesion.Imaging has an essential role in the diagnosis, staging, and management of osteochondral lesions. Many of these lesions are first diagnosed by plain film. MRI adds value by identifying unstable lesions that require surgical intervention. This review focuses on the clinical and imaging features of osteochondral lesions of the knee, elbow, and ankle. Imaging criteria for staging and management are also reviewed.

November 2014

Facing the Future of Brain Tumor Clinical Research.

Gilbert MR, Armstrong TS, Pope WB, van den Bent MJ, Wen PY.

This edition of CCR Focus provides critical reviews of several important areas in the field, including the application of findings from genomic investigations of brain tumors to improve diagnosis, clinical trial design, and ultimately optimizing individual patient treatment. Another article is a critical review provided by experts in the field that discusses the recent clinical trials using angiogenesis inhibitors, possible explanations for the results, and how to move forward. There is a concise discussion of the application of immunotherapy to brain tumors by key investigators in this field, reflecting the potential opportunities as well as the disease-specific challenges. Finally, leading pediatric brain tumor investigators provide an overview of the field and insights about the recent seminal discoveries in two pediatric brain tumors, supporting the paradigm that laboratory investigations lead to more precise diagnosis, prognosis, and ultimately better treatment. Herein, an overview of the recent advances and challenges in the area of clinical and translational brain tumor research is provided to set the stage for the contributions that follow. See all articles in this CCR Focus section, "Discoveries, Challenges, and Progress in Primary Brain Tumors."

November 2014

ACR Appropriateness Criteria® Rib Fractures.

Henry TS, Kirsch J, Kanne JP, Chung JH, Donnelly EF, Ginsburg ME, Heitkamp DE, Kazerooni EA, Ketai LH, McComb BL, Parker JA, Ravenel JG, Restrepo CS, Saleh AG, Shah RD, Steiner RM, Suh RD, Mohammed TL; Expert Panel on Thoracic Imaging:.

Rib fracture is the most common thoracic injury, present in 10% of all traumatic injuries and almost 40% of patients who sustain severe nonpenetrating trauma. Although rib fractures can produce significant morbidity, the diagnosis of associated complications (such as pneumothorax, hemothorax, pulmonary contusion, atelectasis, flail chest, cardiovascular injury, and injuries to solid and hollow abdominal organs) may have a more significant clinical impact. When isolated, rib fractures have a relatively low morbidity and mortality, and failure to detect isolated rib fractures does not necessarily alter patient management or outcome in uncomplicated cases. A standard posteroanterior chest radiograph should be the initial, and often the only, imaging test required in patients with suspected rib fracture after minor trauma. Detailed radiographs of the ribs rarely add additional information that would change treatment, and, although other imaging tests (eg, computed tomography, bone scan) have increased sensitivity for detection of rib fractures, there are little data to support their use. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review process include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

November 2014

Magnetic Resonance Imaging-Ultrasound Fusion Biopsy for Prediction of Final Prostate Pathology.

Le JD, Stephenson S, Brugger M, Lu DY, Lieu P, Sonn GA, Natarajan S, Dorey FJ, Huang J, Margolis DJ, Reiter RE, Marks LS.

PURPOSE: We explored the impact of magnetic resonance imaging-ultrasound fusion prostate biopsy on the prediction of final surgical pathology. MATERIALS AND METHODS: A total of 54 consecutive men undergoing radical prostatectomy at UCLA after fusion biopsy were included in this prospective, institutional review board approved pilot study. Using magnetic resonance imaging-ultrasound fusion, tissue was obtained from a 12-point systematic grid (mapping biopsy) and from regions of interest detected by multiparametric magnetic resonance imaging (targeted biopsy). A single radiologist read all magnetic resonance imaging, and a single pathologist independently rereviewed all biopsy and whole mount pathology, blinded to prior interpretation and matched specimen. Gleason score concordance between biopsy and prostatectomy was the primary end point.

November 2014

Qualitative and Quantitative MDCT Features for Differentiating Clear Cell Renal Cell Carcinoma From Other Solid Renal Cortical Masses.

Lee-Felker SA, Felker ER, Tan N, Margolis DJ, Young JR, Sayre J, Raman SS.

OBJECTIVE. The purpose of this study was to differentiate clear cell renal cell carcinoma (RCC) from other solid renal masses on four-phase MDCT. MATERIALS AND METHODS. Our study cohort included all pathologically proven solid renal masses that underwent pretreatment four-phase MDCT at our institution from 2001 to 2012. Both retrospective qualitative analysis (blinded dual-radiologist evaluation of morphologic features: enhancement pattern, lesion contour, neovascularity, and calcification) and quantitative analysis (mean absolute and relative attenuation and changes in attenuation across phases) were performed. ANOVA with post-hoc analysis, Pearson chi-square tests, and ROC analysis were used.

November 2014

The Cost of Screening Esophageal Varices: Traditional Endoscopy Versus Computed Tomography.

Lotfipour AK, Douek M, Shimoga SV, Sayer JW, Han SB, Jutabha R, Lu DS.

OBJECTIVE: Under current guidelines, patients diagnosed with cirrhosis are to undergo initial and continued screening endoscopy for esophageal varices throughout the course of disease. Recent literature suggests that computed tomography (CT) of the abdomen is adequately sensitive for detecting grade 3 varices, those in need of immediate intervention. This study presents a cost comparison of traditional endoscopy versus CT of the abdomen. METHODS: Using TreeAge Pro software, a budget impact cost model was created for a hypothetical managed care organization covering 1 million lives over a 10-year period. Incidence figures for cirrhosis and the progression of esophageal varices were applied to the patient population. National Medicare reimbursement costs were used to compare screening with traditional endoscopy versus CT. Costs utilizing screening with combined endoscopy and CT were also examined.

November 2014

Intermediate Outcomes and Predictors of Efficacy in the Radiofrequency Ablation of 100 Pathologically Proven Renal Cell Carcinomas.

McClure TD, Chow DS, Tan N, Sayre JA, Pantuck AJ, Raman SS.

PURPOSE: To determine oncologic outcomes and predictors of primary efficacy, including RENAL nephrometry scores (radius, exophytic/endophytic properties, nearness of tumor to collecting system or sinus, anterior/posterior, location relative to polar lines), after percutaneous radiofrequency (RF) ablation of proven renal cell carcinoma (RCC). MATERIALS AND METHODS: Patients who underwent percutaneous computed tomography- and ultrasound-guided RF ablation for histologically proven RCC from 2004 to 2011 were evaluated. Clinical data, pathologic findings, technical details, and outcomes were reviewed. Univariate and multivariate logistic regression analysis was performed to determine predictors of primary technique effectiveness and complications. Local tumor progression-free, metastasis-free, and overall survival were calculated. One hundred RCC lesions underwent 115 RF ablation sessions in 84 patients. Median follow-up was 24 months (mean, 27 mo; range, 1-106 mo).

November 2014

Success Rates for Computed Tomography-guided Musculoskeletal Biopsies Performed Using a Low-dose Technique.

Motamedi K, Levine BD, Seeger LL, McNitt-Gray MF.

OBJECTIVE: To evaluate the success rate of a low-dose (50% mAs reduction) computed tomography (CT) biopsy technique. This protocol was adopted based on other successful reduced-CT radiation dose protocols in our department, which were implemented in conjunction with quality improvement projects. MATERIALS AND METHODS: The technique included a scout view and initial localizing scan with standard dose. Additional scans obtained for further guidance or needle adjustment were acquired by reducing the tube current-time product (mAs) by 50%. The radiology billing data were searched for CT-guided musculoskeletal procedures performed over a period of 8 months following the initial implementation of the protocol. These were reviewed for the type of procedure and compliance with the implemented protocol. The compliant CT-guided biopsy cases were then retrospectively reviewed for patient demographics, tumor pathology, and lesion size. Pathology results were compared to the ultimate diagnoses and were categorized as diagnostic, accurate, or successful.

November 2014

ACR Appropriateness Criteria® on Renal Failure.

Remer EM, Papanicolaou N, Casalino DD, Bishoff JT, Blaufox MD, Coursey CA, Dighe M, Eberhardt SC, Goldfarb S, Harvin HJ, Heilbrun ME, Leyendecker JR, Nikolaidis P, Oto A, Preminger GM, Raman SS, Sheth S, Vikram R, Weinfeld RM.

Imaging plays a role in the management of patients with acute kidney injury or chronic kidney disease. However, clinical circumstances strongly impact the appropriateness of imaging use. In patients with newly detected renal dysfunction, ultrasonography can assess for reversible causes, assess renal size and echogenicity, and thus, establish the chronicity of disease. Urinary obstruction can be detected, but imaging is most useful in high-risk groups or in patients in whom there is a strong clinical suspicion for obstruction. Computed tomography, computed tomography or magnetic resonance arteriography, and percutaneous ultrasound-guided renal biopsy are valuable in other clinical situations. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

November 2014

PD-1 Blockade Induces Responses by Inhibiting Adaptive Immune Resistance.

Tumeh PC, Harview CL, Yearley JH, Shintaku IP, Taylor EJ, Robert L, Chmielowski B, Spasic M, Henry G, Ciobanu V, West AN, Carmona M, Kivork C, Seja E, Cherry G, Gutierrez AJ, Grogan TR, Mateus C, Tomasic G, Glaspy JA, Emerson RO, Robins H, Pierce RH, Elashoff DA, Robert C, Ribas A.

Therapies that target the programmed death-1 (PD-1) receptor have shown unprecedented rates of durable clinical responses in patients with various cancer types. One mechanism by which cancer tissues limit the host immune response is via upregulation of PD-1 ligand (PD-L1) and its ligation to PD-1 on antigen-specific CD8(+) T cells (termed adaptive immune resistance). Here we show that pre-existing CD8(+) T cells distinctly located at the invasive tumour margin are associated with expression of the PD-1/PD-L1 immune inhibitory axis and may predict response to therapy. We analysed samples from 46 patients with metastatic melanoma obtained before and during anti-PD-1 therapy (pembrolizumab) using quantitative immunohistochemistry, quantitative multiplex immunofluorescence, and next-generation sequencing for T-cell antigen receptors (TCRs). In serially sampled tumours, patients responding to treatment showed proliferation of intratumoral CD8(+) T cells that directly correlated with radiographic reduction in tumour size. Pre-treatment samples obtained from responding patients showed higher numbers of CD8-, PD-1- and PD-L1-expressing cells at the invasive tumour margin and inside tumours, with close proximity between PD-1 and PD-L1, and a more clonal TCR repertoire. Using multivariate analysis, we established a predictive model based on CD8 expression at the invasive margin and validated the model in an independent cohort of 15 patients. Our findings indicate that tumour regression after therapeutic PD-1 blockade requires pre-existing CD8(+) T cells that are negatively regulated by PD-1/PD-L1-mediated adaptive immune resistance.

November 2014

MRI Criteria for the Diagnosis of Pleomorphic Adenoma: a Validation Study.

Zaghi S, Hendizadeh L, Hung T, Farahvar S, Abemayor E, Sepahdari AR.

OBJECTIVES: To validate an MRI algorithm characteristic of pleomorphic adenoma (PA). STUDY DESIGN: Cross-sectional analysis. SETTING: Academic tertiary-care medical center. METHODS: A radiologic algorithm for the MRI diagnosis of PA was developed on the basis of five "high probability" criteria that all must be fulfilled for the MRI to qualify as a positive test result: bright T2-signal, sharp margins, heterogeneous nodular enhancement, lobulated contours, T2-dark rim. We then identified MRI images from our institutional database to test the diagnostic accuracy of the proposed algorithm.

October 2014

Image-guided Tumor Ablation: Standardization of Terminology and Reporting Criteria-A 10-Year Update.

Ahmed M, Solbiati L, Brace CL, Breen DJ, Callstrom MR, Charboneau JW, Chen MH, Choi BI, de Baère T, Dodd GD 3rd, Dupuy DE, Gervais DA, Gianfelice D, Gillams AR, Lee FT Jr, Leen E, Lencioni R, Littrup PJ, Livraghi T, Lu DS, McGahan JP, Meloni MF, Nikolic B, Pereira PL, Liang P, Rhim H, Rose SC, Salem R, Sofocleous CT, Solomon SB, Soulen MC, Tanaka M, Vogl TJ, Wood BJ, Goldberg SN; International Working Group on Image-guided Tumor Ablation, Interventional Oncology Sans Frontières Expert Panel, Technology Assessment Committee of the Society of Interventional Radiology, and the Standard of Practice Committee of the Cardiovascular and Interventional Radiological Society of Europe.

Image-guided tumor ablation has become a well-established hallmark of local cancer therapy. The breadth of options available in this growing field increases the need for standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison among treatments that use different technologies, such as chemical (eg, ethanol or acetic acid) ablation, thermal therapies (eg, radiofrequency, laser, microwave, focused ultrasound, and cryoablation) and newer ablative modalities such as irreversible electroporation. This updated consensus document provides a framework that will facilitate the clearest communication among investigators regarding ablative technologies. An appropriate vehicle is proposed for reporting the various aspects of image-guided ablation therapy including classification of therapies, procedure terms, descriptors of imaging guidance, and terminology for imaging and pathologic findings. Methods are addressed for standardizing reporting of technique, follow-up, complications, and clinical results. As noted in the original document from 2003, adherence to the recommendations will improve the precision of communications in this field, leading to more accurate comparison of technologies and results, and ultimately to improved patient outcomes.

October 2014

Correlation of Quantitative Diffusion-Weighted and Dynamic Contrast-enhanced MRI Parameters with Prognostic Factors in Prostate Cancer.

Chung MP, Margolis D, Mesko S, Wang J, Kupelian P, Kamrava M.

INTRODUCTION: The aim of this study was to determine if correlations exist between quantitative parameters from dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) MRI with National Comprehensive Cancer Network (NCCN) risk group, Gleason score (GS), maximum tumour diameter (MTD), pre-treatment prostate-specific antigen (PSA), clinical T stage and MRI prostate volume in prostate cancer. METHOD: We retrospectively reviewed 3T multiparametric MRI reports on biopsy-proven prostate cancer patients performed during radiation treatment evaluation or an active surveillance protocol. DCE-MRI parameters included K(trans) (influx volume transfer coefficient), Kep (efflux reflux rate constant) and iAUC (initial area under the curve). Average DCE and apparent diffusion coefficient (ADC) values were recorded for regions of interest on DW-MRI. Relationships between MRI metrics and risk group, GS, MTD, PSA, clinical T stage and MRI prostate volume were examined using analysis of variance. Central and peripheral tumours were also analysed separately in a sub-analysis. Statistical significance was defined as P < 0.0125.

October 2014

Emerging Techniques and Technologies in Brain Tumor Imaging.

Ellingson BM, Bendszus M, Sorensen AG, Pope WB.

The purpose of this report is to describe the state of imaging techniques and technologies for detecting response of brain tumors to treatment in the setting of multicenter clinical trials. Within currently used technologies, implementation of standardized image acquisition and the use of volumetric estimates and subtraction maps are likely to help to improve tumor visualization, delineation, and quantification. Upon further development, refinement, and standardization, imaging technologies such as diffusion and perfusion MRI and amino acid PET may contribute to the detection of tumor response to treatment, particularly in specific treatment settings. Over the next few years, new technologies such as 23Na MRI and CEST imaging technologies will be explored for their use in expanding the ability to quantitatively image tumor response to therapies in a clinical trial setting.

October 2014

Pros and Cons of Current Brain Tumor Imaging.

Ellingson BM, Wen PY, van den Bent MJ, Cloughesy TF.

Over the past 20 years, very few agents have been approved for the treatment of brain tumors. Recent studies have highlighted some of the challenges in assessing activity in novel agents for the treatment of brain tumors. This paper reviews some of the key challenges related to assessment of tumor response to therapy in adult high-grade gliomas and discusses the strengths and limitations of imaging-based endpoints. Although overall survival is considered the "gold standard" endpoint in the field of oncology, progression-free survival and response rate are endpoints that hold great value in neuro-oncology. Particular focus is given to advancements made since the January 2006 Brain Tumor Endpoints Workshop, including the development of Response Assessment in Neuro-Oncology criteria, the value of T2/fluid-attenuated inversion recovery, use of objective response rates and progression-free survival in clinical trials, and the evaluation of pseudoprogression, pseudoresponse, and inflammatory response in radiographic images.

October 2014

A Pilot Validation of Multi-echo Based Echo-planar Correlated Spectroscopic Imaging in Human Calf Muscles.

Furuyama JK, Nagarajan R, Roberts CK, Lee CC, Hahn TJ, Thomas MA.

A current limitation of MR spectroscopic imaging of multiple skeletal muscles is prolonged scan duration. A significant reduction in the total scan duration using the echo-planar correlated spectroscopic imaging (EP-COSI) sequence was accomplished using two bipolar readout trains with different phase-encoded echoes for one of two spatial dimensions within a single repetition time (TR). The second bipolar readout was used for spatially encoding the outer k-space, whereas the first readout was used for the central k-space only. The performance of this novel sequence, called multi-echo based echo-planar correlated spectroscopic imaging (ME-EPCOSI), was demonstrated by localizing specific key features in calf muscles and bone marrow of 11 healthy volunteers and five subjects with type 2 diabetes (T2D). A 3 T MRI-MRS scanner equipped with a transmit-receive extremity coil was used. Localization of the ME-EPCOSI sequence was in good agreement with the earlier single-readout based EP-COSI sequence and the required scan time was reduced by a factor of two. In agreement with an earlier report using single-voxel based 2D MRS, significantly increased unsaturated pools of intramyocellular lipid (IMCL) and extramyocellular lipid (EMCL) and decreased IMCL and EMCL unsaturation indices (UIs) were observed in the soleus and tibialis anterior muscle regions of subjects with T2D compared with healthy controls. In addition, significantly decreased choline content was observed in the soleus of T2D subjects compared with healthy controls. Multi-voxel characterization of IMCL and EMCL ratios and UI in the calf muscle may be useful for the non-invasive assessment of altered lipid metabolism in the pathophysiology of T2D.

October 2014

Projected Outcomes Using Different Nodule Sizes to Define a Positive CT Lung Cancer Screening Examination.

Gierada DS, Pinsky P, Nath H, Chiles C, Duan F, Aberle DR.

BACKGROUND: Computed tomography (CT) screening for lung cancer has been associated with a high frequency of false positive results because of the high prevalence of indeterminate but usually benign small pulmonary nodules. The acceptability of reducing false-positive rates and diagnostic evaluations by increasing the nodule size threshold for a positive screen depends on the projected balance between benefits and risks. METHODS: We examined data from the National Lung Screening Trial (NLST) to estimate screening CT performance and outcomes for scans with nodules above the 4mm NLST threshold used to classify a CT screen as positive. Outcomes assessed included screening results, subsequent diagnostic tests performed, lung cancer histology and stage distribution, and lung cancer mortality. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for the different nodule size thresholds. All statistical tests were two-sided.

October 2014

Coil-Assisted Retrograde Transvenous Obliteration (CARTO) for the Treatment of Portal Hypertensive Variceal Bleeding: Preliminary Results.

Lee EW, Saab S, Gomes AS, Busuttil R, McWilliams J, Durazo F, Han SH, Goldstein L, Tafti BA, Moriarty J, Loh CT, Kee ST.

OBJECTIVES: To describe the technical feasibility, safety, and clinical outcomes of coil-assisted retrograde transvenous obliteration (CARTO) in treating portal hypertensive non-esophageal variceal hemorrhage. METHODS: From October 2012 to December 2013, 20 patients who received CARTO for the treatment of portal hypertensive non-esophageal variceal bleeding were retrospectively evaluated. All 20 patients had at least 6-month follow-up. All patients had detachable coils placed to occlude the efferent shunt and retrograde gelfoam embolization to achieve complete thrombosis/obliteration of varices. Technical success, clinical success, rebleeding, and complications were evaluated at follow-up.

October 2014

In vivo (1) H MRS of Human Gallbladder Bile at 3 T in One and Two Dimensions: Detection and Quantification of Major Biliary Lipids.

Mohajeri S, Ijare OB, Bezabeh T, King SB, Thomas MA, Minuk G, Lipschitz J, Kirkpatrick I, Smith M, Smith IC.

In vitro (1)H MRS of human bile has shown potential in the diagnosis of various hepatopancreatobiliary (HPB) diseases. Previously, in vivo (1)H MRS of human bile in gallbladder using a 1.5 T scanner demonstrated the possibility of quantification of choline-containing phospholipids (chol-PLs). However, other lipid components such as bile acids play an important role in the pathophysiology of the HPB system. We have employed a higher magnetic field strength (3 T), and a custom-built receive array coil, to improve the quality of in vivo (1)H MRS of human bile in the gallbladder. We obtained significant improvement in the quality of 1D spectra (17 healthy volunteers) using a respiratory-gated PRESS sequence with well distinguished signals for total bile acids (TBAs) plus cholesterol resonating at 0.66 ppm, taurine-conjugated bile acids (TCBAs) at 3.08 ppm, chol-PLs at 3.22 ppm, glycine-conjugated bile acids (GCBAs) at 3.74 ppm, and the amide proton (-NH) arising from GCBAs and TCBAs in the region 7.76-8.05 ppm. The peak areas of these signals were measured by deconvolution, and subsequently the molar concentrations of metabolites were estimated with good accuracy, except for that of TBAs plus cholesterol. The concentration of TBAs plus cholesterol was overestimated in some cases, which could be due to lipid contamination. In addition, we report the first 2D L-COSY spectra of human gallbladder bile in vivo (obtained in 15 healthy volunteers). 2D L-COSY spectra will be helpful in differentiating various biliary chol-PLs in pathological conditions of the HPB system.

October 2014

Impact of Imaging Measurements on Response Assessment in Glioblastoma Clinical Trials.

Reardon DA, Ballman KV, Buckner JC, Chang SM, Ellingson BM.

We provide historical and scientific guidance on imaging response assessment for incorporation into clinical trials to stimulate effective and expedited drug development for recurrent glioblastoma by addressing 3 fundamental questions: (i) What is the current validation status of imaging response assessment, and when are we confident assessing response using today's technology? (ii) What imaging technology and/or response assessment paradigms can be validated and implemented soon, and how will these technologies provide benefit? (iii) Which imaging technologies need extensive testing, and how can they be prospectively validated? Assessment of T1 +/- contrast, T2/FLAIR, diffusion, and perfusion-imaging sequences are routine and provide important insight into underlying tumor activity. Nonetheless, utility of these data within and across patients, as well as across institutions, are limited by challenges in quantifying measurements accurately and lack of consistent and standardized image acquisition parameters. Currently, there exists a critical need to generate guidelines optimizing and standardizing MRI sequences for neuro-oncology patients. Additionally, more accurate differentiation of confounding factors (pseudoprogression or pseudoresponse) may be valuable. Although promising, diffusion MRI, perfusion MRI, MR spectroscopy, and amino acid PET require extensive standardization and validation. Finally, additional techniques to enhance response assessment, such as digital T1 subtraction maps, warrant further investigation.

October 2014

Report of the Jumpstarting Brain Tumor Drug Development Coalition and FDA Clinical Trials Neuroimaging Endpoint Workshop (January 30, 2014, Bethesda MD).

Wen PY, Cloughesy TF, Ellingson BM, Reardon DA, Fine HA, Abrey L, Ballman K, Bendszuz M, Buckner J, Chang SM, Prados MD, Pope WB, Gregory Sorensen A, van den Bent M, Yung WK.

On January 30, 2014, a workshop was held on neuroimaging endpoints in high-grade glioma. This workshop was sponsored by the Jumpstarting Brain Tumor Drug Development Coalition, consisting of the National Brain Tumor Society, the Society for Neuro-Oncology, Accelerate Brain Cancer Cure, and the Musella Foundation for Research and Information, and conducted in collaboration with the Food and Drug Administration. The workshop included neuro-oncologists, neuroradiologists, radiation oncologists, neurosurgeons, biostatisticians, patient advocates, and representatives from industry, clinical research organizations, and the National Cancer Institute. This report summarizes the presentations and discussions of that workshop and the proposals that emerged to improve the Response Assessment in Neuro-Oncology (RANO) criteria and standardize neuroimaging parameters.

September 2014

Actionable Reporting.

Boland GW, Enzmann DR, Duszak R Jr.

Ultimately, any business is only as strong as the weakest link in its operational chain. This series has used the concept of the imaging value chain to identify sources of potential weakness and error within the imaging enterprise and then offered practical solutions for remedying those weaknesses to optimize patient care. In this column, we address the end product of all radiologic services, the imaging report.

September 2014

A Survey of Breast Imaging Fellowship Programs: Current Status of Curriculum and Training in the United States and Canada.

Farria DM, Salcman J, Monticciolo DL, Monsees BS, Rebner M, Bassett LW.

PURPOSE: The Society of Breast Imaging and the Education Committee of the ACR Breast Commission conducted a survey of breast imaging fellowship programs to determine the status of fellowship curricula, help identify strengths and potential areas for improvement, and assess the current demand for fellowship programs. METHODS: In 2012, a two-part survey was emailed to breast imaging fellowship directors from 72 fellowship programs.

September 2014

ACR Appropriateness Criteria® Nontraumatic Aortic Disease.

Kalva SP, Dill KE, Bandyk DF, Francois CJ, Gerhard-Herman MD, Hanley M, Mohler ER 3rd, Moriarty JM, Oliva IB, Schenker MP, Weiss C, Rybicki FJ; Expert Panel on Vascular Imaging:.

The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. In this document we provided guidelines for use of various imaging modalities for assessment of nontraumatic aortic diseases.

September 2014

Subcutaneous Panniculitis-like T-cell Lymphoma: MRI Features and Literature Review.

Levine BD, Seeger LL, James AW, Motamedi K.

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) represents a rare subclassification of peripheral T-cell lymphoma (PTCL). We present a case of a 21-year-old female who presented with a 1-month history of pain in the left buttock and hip, tender left inguinal lymph nodes, fevers, and night sweats. Percutaneous core needle biopsy was diagnostic for SPTCL with CD8+ cells positive for cytotoxic granules. Magnetic resonance imaging (MRI) features of SPTCL with a review of the literature are discussed.

September 2014

Society of Interventional Radiology Position Statement: Prostate Artery Embolization for Treatment of Benign Disease of the Prostate.

McWilliams JP, Kuo MD, Rose SC, Bagla S, Caplin DM, Cohen EI, Faintuch S, Spies JB, Saad WE, Nikolic B.

Prostatic artery embolization (PAE) is a promising new treatment for lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). It has therefore garnered much interest in the interventional community. This article will review the scientific background for this therapy, describe the current devices available for treatment, and state the position of the Society of Interventional Radiology (SIR) with regard to the study and potential adoption of this therapy.

September 2014

Diffusion-Weighted Imaging in Cancer: Physical Foundations and Applications of Restriction Spectrum Imaging.

White NS, McDonald CR, Farid N, Kuperman J, Karow D, Schenker-Ahmed NM, Bartsch H, Rakow-Penner R, Holland D, Shabaik A, Bjørnerud A, Hope T, Hattangadi-Gluth J, Liss M, Parsons JK, Chen CC, Raman S, Margolis D, Reiter RE, Marks L, Kesari S, Mundt AJ, Kaine CJ, Carter BS, Bradley WG, Dale AM.

Diffusion-weighted imaging (DWI) has been at the forefront of cancer imaging since the early 2000s. Before its application in clinical oncology, this powerful technique had already achieved widespread recognition due to its utility in the diagnosis of cerebral infarction. Following this initial success, the ability of DWI to detect inherent tissue contrast began to be exploited in the field of oncology. Although the initial oncologic applications for tumor detection and characterization, assessing treatment response, and predicting survival were primarily in the field of neurooncology, the scope of DWI has since broadened to include oncologic imaging of the prostate gland, breast, and liver. Despite its growing success and application, misconceptions about the underlying physical basis of the DWI signal exist among researchers and clinicians alike. In this review, we provide a detailed explanation of the biophysical basis of diffusion contrast, emphasizing the difference between hindered and restricted diffusion, and elucidating how diffusion parameters in tissue are derived from the measurements via the diffusion model. We describe one advanced DWI modeling technique, called restriction spectrum imaging (RSI). This technique offers a more direct in vivo measure of tumor cells, due to its ability to distinguish separable pools of water within tissue based on their intrinsic diffusion characteristics. Using RSI as an example, we then highlight the ability of advanced DWI techniques to address key clinical challenges in neurooncology, including improved tumor conspicuity, distinguishing actual response to therapy from pseudoresponse, and delineation of white matter tracts in regions of peritumoral edema. We also discuss how RSI, combined with new methods for correction of spatial distortions inherent in diffusion MRI scans, may enable more precise spatial targeting of lesions, with implications for radiation oncology and surgical planning.

August 2014

Reply to 're: "Evaluating Patency Rates of an Ultralow-porosity Expanded Polytetrafluoroethylene-covered Stent in the Treatment of Venous Stenosis in Arteriovenous Dialysis Circuits"'.

Chan MG, Miller FJ, Valji K, Kuo MD.

We appreciate the points raised by Dolmatch (1) concerning the use of the VIABIL biliary stent-graft (W.L. Gore and Associates, Flagstaff, Arizona) for venous outflow stenoses in arteriovenous grafts and fistulae. Although it is certainly not our contention that stent-grafts should be used routinely in an off-label fashion—a point we make clear in our article (2)—our goal was merely to evaluate a timely and pressing unmet medical need confounding a specific patient population when the study was performed. Indeed, the data were obtained more than 5 years ago, primarily at a time when no stent-graft options for dialysis access circuits existed, and any stent-grafts used in dialysis access circuits would, by necessity, be used on an off-label basis....

August 2014

The THRIVE Score Strongly Predicts Outcomes in Patients Treated with the Solitaire Device in the SWIFT and STAR Trials.

Flint AC, Cullen SP, Rao VA, Faigeles BS, Pereira VM, Levy EI, Jovin TG, Liebeskind DS, Nogueira RG, Jahan R, Saver JL; SWIFT and STAR trialists.

BACKGROUND: The Totaled Health Risks in Vascular Events (THRIVE) score strongly predicts clinical outcome, mortality, and risk of thrombolytic haemorrhage in ischemic stroke patients, and performs similarly well in patients receiving intravenous tissue plasminogen activator, endovascular stroke treatment, or no acute treatment. It is not known if the THRIVE score predicts outcomes with the Solitaire endovascular stroke treatment device. AIMS: To validate the relationship between the THRIVE score and outcomes after treatment with the Solitaire endovascular stroke treatment device. METHODS: The study conducted a retrospective analysis of the prospective SWIFT and STAR trials to examine the relationship between THRIVE and outcomes after treatment with the Solitaire device. We examined the relationship between THRIVE and clinical outcomes (good outcome or death at 90 days) among patients in SWIFT and STAR. Receiver-operator characteristics curve analysis was used to compare THRIVE score performance with other stroke prediction scores. Multivariable modeling was used to confirm the independence of the THRIVE score from procedure-specific predictors (successful recanalization or device used) and other predictors of functional outcome.

August 2014

Comparison of Simulated Structural Deformation with Experimental Results after Wingspan Stenting.

Fujimoto M, Shobayashi Y, Tateshima S, Sudo R, Tanishita K, Viñuela F.

OBJECTIVES: Biomechanical stress distribution correlates with the biological responses after stenting. Computational analyses have contributed to the optimization of stent geometry. In particular, structural analysis based on pre-operative angiography can be used to predict the stent-artery interaction before endovascular treatments. However, the simulated results need to be validated. In this report, we compared the simulated arterial structure with post-operative images after an intracranial Wingspan stent. METHODS: A Wingspan stent was deployed at a slightly curved ascending pharyngeal artery (APA) in the swine. Using a finite element method (FEM), the configuration after stenting was simulated and quantitatively compared with post-procedural 3D angiography.

August 2014

Targeted Prostate Biopsy in Select Men for Active Surveillance-do the Epstein Criteria Still Apply?

Hu JC, Chang E, Natarajan S, Margolis DJ, Macairan M, Lieu P, Huang J, Sonn G, Dorey FJ, Marks LS.

PURPOSE: Established in 1994, the Epstein histological criteria (Gleason score 6 or less, 2 or fewer cores positive and 50% or less of any core) have been widely used to select men for active surveillance. However, with the advent of targeted biopsy, which may be more accurate than conventional biopsy, we reevaluated the likelihood of reclassification upon confirmatory rebiopsy using multiparametric magnetic resonance imaging-ultrasound fusion. MATERIALS AND METHODS: We identified 113 men enrolled in active surveillance at our institution who met Epstein criteria and subsequently underwent confirmatory targeted biopsy via multiparametric magnetic resonance imaging-ultrasound fusion. Median patient age was 64 years, median prostate specific antigen was 4.2 ng/ml and median prostate volume was 46.8 cc. Targets or regions of interest on multiparametric magnetic resonance imaging-ultrasound fusion were graded by suspicion level and biopsied at 3 mm intervals along the longest axis (median 10.5 mm). Also, 12 systematic cores were obtained during confirmatory rebiopsy. Our reporting is consistent with START (Standards of Reporting for MRI-targeted Biopsy Studies) criteria.

August 2014

Interactive Lung Segmentation in Abnormal Human and Animal Chest CT Scans.

Kockelkorn TT, Schaefer-Prokop CM, Bozovic G, Muñoz-Barrutia A, van Rikxoort EM, Brown MS, de Jong PA, Viergever MA, van Ginneken B.

PURPOSE: Many medical image analysis systems require segmentation of the structures of interest as a first step. For scans with gross pathology, automatic segmentation methods may fail. The authors' aim is to develop a versatile, fast, and reliable interactive system to segment anatomical structures. In this study, this system was used for segmenting lungs in challenging thoracic computed tomography (CT) scans. METHODS: In volumetric thoracic CT scans, the chest is segmented and divided into 3D volumes of interest (VOIs), containing voxels with similar densities. These VOIs are automatically labeled as either lung tissue or nonlung tissue. The automatic labeling results can be corrected using an interactive or a supervised interactive approach. When using the supervised interactive system, the user is shown the classification results per slice, whereupon he/she can adjust incorrect labels. The system is retrained continuously, taking the corrections and approvals of the user into account. In this way, the system learns to make a better distinction between lung tissue and nonlung tissue. When using the interactive framework without supervised learning, the user corrects all incorrectly labeled VOIs manually. Both interactive segmentation tools were tested on 32 volumetric CT scans of pigs, mice and humans, containing pulmonary abnormalities.

August 2014

Efficacy of the American Association for the Study of Liver Disease and Barcelona Criteria for the Diagnosis of Hepatocellular Carcinoma.

Pahwa A, Beckett K, Channual S, Tan N, Lu DS, Raman SS.

OBJECTIVES: Dynamic contrast-enhanced CT scan and MRI are essential for preoperative diagnosis of hepatocellular carcinoma (HCC), using the established Barcelona and AASLD criteria, which have been validated in only a few reports. The aim of this study is to retrospectively assess the diagnostic performance of these criteria in diagnosing or excluding HCC in at-risk patients with histopathology confirmation. METHODS: After institutional review board approval, a HIPAA compliant study was performed. The study cohort consisted of 156 de novo hepatic nodules imaged by either dynamic contrast-enhanced CT or MRI within 90 days of histopathology. Images were retrospectively reviewed by two abdominal radiologists blinded to clinical details, and all nodules were categorized as either meeting or not meeting AASLD and Barcelona criteria. By AASLD or Barcelona criteria, HCC was defined as any nodule greater than or equal to 1 or 2 cm, respectively, with hyperenhancement relative to background liver on arterial phase and hypoenhancement relative to background liver on portal venous or delayed phases. Significant differences in cohorts were analyzed using chi squared analysis (p < 0.05).

August 2014

Target Detection: Magnetic Resonance Imaging-ultrasound Fusion-guided Prostate Biopsy.

Sonn GA, Margolis DJ, Marks LS.

Recent advances in multiparametric magnetic resonance imaging (MRI) have enabled image-guided detection of prostate cancer. Fusion of MRI with real-time ultrasound (US) allows the information from MRI to be used to direct biopsy needles under US guidance in an office-based procedure. Fusion can be performed either cognitively or electronically, using a fusion device. Fusion devices allow superimposition (coregistration) of stored MRI images on real-time US images; areas of suspicion found on MRI can then serve as targets during US-guided biopsy. Currently available fusion devices use a variety of technologies to perform coregistration: robotic tracking via a mechanical arm with built-in encoders (Artemis/Eigen, BioJet/Geoscan); electromagnetic tracking (UroNav/Philips-Invivo, Hi-RVS/Hitachi); or tracking with a 3D US probe (Urostation/Koelis). Targeted fusion biopsy has been shown to identify more clinically significant cancers and fewer insignificant cancers than conventional biopsy. Fusion biopsy appears to be a major advancement over conventional biopsy because it allows (1) direct targeting of suspicious areas not seen on US and (2) follow-up biopsy of specific cancerous sites in men undergoing active surveillance.

August 2014

ALK Molecular Phenotype in Non-Small Cell Lung Cancer: CT Radiogenomic Characterization.

Yamamoto S, Korn RL, Oklu R, Migdal C, Gotway MB, Weiss GJ, Iafrate AJ, Kim DW, Kuo MD.

Purpose To present a radiogenomic computed tomographic (CT) characterization of anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC) (ALK+). Materials and Methods In this HIPAA-compliant institutional review board-approved retrospective study, CT studies, ALK status, and clinical-pathologic data in 172 patients with NSCLC from three institutions were analyzed. A screen of 24 CT image traits was performed in a training set of 59 patients, followed by random forest variable selection incorporating 24 CT traits plus six clinical-pathologic covariates to identify a radiogenomic predictor of ALK+ status. This predictor was then validated in an independent cohort (n = 113). Test-for-accuracy and subset analyses were performed. A similar analysis was performed to identify a biomarker associated with shorter progression-free survival (PFS) after therapy with the ALK inhibitor crizotinib. Results ALK+ status was associated with central tumor location, absence of pleural tail, and large pleural effusion. An ALK+ radiogenomic CT status biomarker consisting of these three imaging traits with patient age of younger than 60 years showed strong discriminatory power for ALK+ status, with a sensitivity of 83.3% (15 of 18), a specificity of 77.9% (74 of 95), and an accuracy of 78.8% (89 of 113) in independent testing. The discriminatory power was particularly strong in patients with operable disease (stage IIIA or lower), with a sensitivity of 100.0% (five of five), a specificity of 88.1% (37 of 42), and an accuracy of 89.4% (42 of 47). Tumors with a disorganized vessel pattern had a shorter PFS with crizotinib therapy than tumors without this trait (11.4 vs 20.2 months, P = .041). Conclusion ALK+ NSCLC has distinct characteristics at CT imaging that, when combined with clinical covariates, discriminate ALK+ from non-ALK tumors and can potentially identify patients with a shorter durable response to crizotinib.

August 2014

Giant Left Atrial Appendage Mimicking a Mediastinal Mass in a New Diagnosis of Atrial Septal Defect and Pulmonic Stenosis.

Yang EH, Moriarty JM, Lluri G, Aboulhosn JA.

We present the case of a 44 year old female, with a history of Down syndrome and a cardiac murmur diagnosed in childhood, who presented to the clinic after she was hospitalized at an outside facility for a new onset of heart failure. Her physical exam was significant for a Grade III/VI midsystolic murmur heard best at the left upper sterna border which accentuated with inspiration, a loud, fixed P2 component of her S2 heart sound. No significant right ventricular heave was felt upon examination. Mild clubbing without cyanosis was also seen. A 12-lead electrocardiogram was significant for right axis deviation and criteria for right ventricular hypertrophy. A transthoracic echocardiogram revealed right sided enlargement and significant right to left interatrial shunting with contrast injection consistent with a possible atrial septal defect (ASD). Pulmonic valve stenosis was also seen. A chest radiograph showed an enlarged cardiac silhouette and a soft tissue bulge along the left heart border concerning for a mediastinal mass. Dual source 128-slice cardiac multidetector computed tomography (MDCT) revealed a large, L-shaped left atrial appendage (LAA) extending over the left lateral aspect with no thrombus which correlated with the suspected mediastinal mass...

July 2014

Computed Tomography Angiography of Lower Extremities in the Emergency Room for Evaluation of Patients with Gunshot Wounds.

Adibi A, Krishnam MS, Dissanayake S, Plotnik AN, Mohajer K, Arellano C, Ruehm SG.

OBJECTIVE: To assess the role of CT angiography in the evaluation of patients with lower extremity gunshot wounds in the emergency room. MATERIALS AND METHODS: Eighty patients (73 male, 7 female, mean age 26 years) underwent CT angiography for the evaluation of lower extremity gunshot injuries. Imaging was conducted on the basis of standardized protocols utilizing 16-slice and 64-slice multidetector systems and images were qualitatively graded and assessed for various forms of arterial injury.

July 2014

Novel Techniques for Sentinel Lymph Node Biopsy in Breast Cancer: a Systematic Review.

Ahmed M, Purushotham AD, Douek M.

The existing standard for axillary lymph node staging in breast cancer patients with a clinically and radiologically normal axilla is sentinel lymph node biopsy with a radioisotope and blue dye (dual technique). The dependence on radioisotopes means that uptake of the procedure is limited to only about 60% of eligible patients in developed countries and is negligible elsewhere. We did a systematic review to assess three techniques for sentinel lymph node biopsy that are not radioisotope dependent or that refine the existing method: indocyanine green fluorescence, contrast-enhanced ultrasound using microbubbles, and superparamagnetic iron oxide nanoparticles. Our systematic review suggested that these new methods for sentinel lymph node biopsy have clinical potential but give high levels of false-negative results. We could not identify any technique that challenged the existing standard procedure. Further assessment of these techniques against the standard dual technique in randomised trials is needed.

July 2014

Pulmonary Coccidioidomycosis: Pictorial Review of Chest Radiographic and CT Findings.

Jude CM, Nayak NB, Patel MK, Deshmukh M, Batra P.

Pulmonary coccidioidomycosis is a fungal disease endemic to the desert regions of the southwestern United States, Mexico, Central America, and South America. The incidence of reported disease increased substantially between 1998 and 2011, and the infection is encountered beyond the endemic areas because of a mobile society. The disease is caused by inhalation of spores of Coccidioides species. Individuals at high risk are those exposed to frequent soil aerosolization. The diagnosis is established by direct visualization of mature spherules by using special stains or cultures from biologic specimens. Serologic testing of anticoccidioidal antibodies is used for diagnosis and treatment monitoring. The infection is self-limited in 60% of cases. When the disease is symptomatic, the lung is the primary site of involvement. On the basis of clinical presentation and imaging abnormalities, pulmonary involvement is categorized into acute, disseminated, and chronic forms, each with a spectrum of imaging findings. In patients with acute disease, the most common findings are lobar or segmental consolidation, multifocal consolidation, and nodules. Adenopathy and pleural effusions are also seen, usually in association with parenchymal disease. Disseminated disease is rare and occurs in less than 1% of patients. Pulmonary findings are miliary nodules and confluent parenchymal opacities. Acute respiratory distress syndrome is an infrequent complication of disseminated disease. The acute findings resolve in most patients, with chronic changes developing in approximately 5% of patients. Manifestations of chronic disease include residual nodules, chronic cavities, persistent pneumonia with or without adenopathy, pleural effusion, and regressive changes. Unusual complications of chronic disease are mycetoma, abscess formation, and bronchopleural fistula. Patients in an immunocompromised state, those with diabetes mellitus, pregnant women, and those belonging to certain ethnic groups may show severe, progressive, or disseminated disease.

July 2014

Impact of Collaterals on Successful Revascularization in Solitaire FR With the Intention for Thrombectomy.

Liebeskind DS, Jahan R, Nogueira RG, Zaidat OO, Saver JL; SWIFT Investigators.

BACKGROUND AND PURPOSE: Collaterals at angiography before endovascular therapy were analyzed to ascertain the effect on a novel end point of successful revascularization without symptomatic hemorrhage in the Solitaire FR With the Intention for Thrombectomy (SWIFT) study. METHODS: Collateral grade (American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology) on baseline angiography was independently assessed, blind to other data, with statistical analyses delineating the relationship with clinical, laboratory, and imaging parameters.

July 2014

Safety of Hydroinfusion in Percutaneous Thermal Ablation of Hepatic Malignancies.

McWilliams JP, Plotnik AN, Sako EY, Raman SS, Tan N, Siripongsakun S, Douek M, Lu DS.

PURPOSE: Hydroinfusion is a commonly used ancillary procedure during percutaneous thermal ablation of the liver that is used to separate and protect sensitive structures from the ablation zone. However, risks of hydroinfusion have not been systematically studied. The purpose of the present study was to systematically examine the frequency and severity of local and systemic complications related to hydroinfusion. MATERIALS AND METHODS: From January 2009 to April 2012, 410 consecutive patients underwent percutaneous thermal hepatic tumor ablation. One hundred fifty patients in the study group underwent hydroinfusion and 260 in the control group did not. Patient charts and imaging studies of both groups were reviewed to compare incidences of complications that could potentially be caused by hydroinfusion, including pleural effusion, bowel injury, infection, electrolyte imbalance, and hyperglycemia.

July 2014

Six-minute Magnetic Resonance Imaging Protocol for Evaluation of Acute Ischemic Stroke: Pushing the Boundaries.

Nael K, Khan R, Choudhary G, Meshksar A, Villablanca P, Tay J, Drake K, Coull BM, Kidwell CS.

BACKGROUND AND PURPOSE: If magnetic resonance imaging (MRI) is to compete with computed tomography for evaluation of patients with acute ischemic stroke, there is a need for further improvements in acquisition speed. METHODS: Inclusion criteria for this prospective, single institutional study were symptoms of acute ischemic stroke within 24 hours onset, National Institutes of Health Stroke Scale ≥3, and absence of MRI contraindications. A combination of echo-planar imaging (EPI) and a parallel acquisition technique were used on a 3T magnetic resonance (MR) scanner to accelerate the acquisition time. Image analysis was performed independently by 2 neuroradiologists.

July 2014

SOLITAIRE™ with the Intention for Thrombectomy (SWIFT) Trial: Design of a Randomized, Controlled, Multicenter Study Comparing the SOLITAIRE™ Flow Restoration Device and the MERCI Retriever in Acute Ischaemic Stroke.

Saver JL, Jahan R, Levy EI, Jovin TG, Baxter B, Nogueira R, Clark W, Budzik R, Zaidat OO; SWIFT Trialists.

RATIONALE: Self-expanding stent retrievers are a promising new device class designed for rapid flow restoration in acute cerebral ischaemia. The SOLITAIRE™ Flow Restoration device (SOLITAIRE) has shown high rates of recanalization in preclinical models and in uncontrolled clinical series. AIMS: (1) To demonstrate non-inferiority of SOLITAIRE compared with a legally marketed device, the MERCI Retrieval System®; (2) To demonstrate safety, feasibility, and efficacy of SOLITAIRE in subjects requiring mechanical thrombectomy diagnosed with acute ischaemic stroke. DESIGN: Multicenter, randomized, prospective, controlled trial with blinded primary end-point ascertainment. STUDY PROCEDURES: Key entry criteria include: age 22-85; National Institute of Health Stroke Scale (NIHSS) ≥8 and <30; clinical and imaging findings consistent with acute ischaemic stroke; patient ineligible or failed intravenous tissue plasminogen activator; accessible occlusion in M1 or M2 middle cerebral artery, internal carotid artery, basilar artery, or vertebral artery; and patient able to be treated within 8h of onset. Sites first participate in a roll-in phase, treating two patients with the SOLITAIRE device, before proceeding to the randomized phase. In patients unresponsive to the initially assigned therapy, after the angiographic component of the primary end-point is ascertained (reperfusion with the initial assigned device), rescue therapy with other reperfusion techniques is permitted.

July 2014

Treatment Response Evaluation Using 18F-FDOPA PET in Patients with Recurrent Malignant Glioma on Bevacizumab Therapy.

Schwarzenberg J, Czernin J, Cloughesy TF, Ellingson BM, Pope WB, Grogan T, Elashoff D, Geist C, Silverman DH, Phelps ME, Chen W.

PURPOSE: This study compares the value of 3,4-dihydroxy-6-[(18)F]-fluoro-l-phenylalanine ((18)F-FDOPA) positron emission tomography (PET) and MRI in assessing outcome during antiangiogenic treatment in patients with recurrent high-grade gliomas. EXPERIMENTAL DESIGN: Thirty patients were prospectively studied with (18)F-FDOPA PET scans immediately before, and two and six weeks after start of bevacizumab therapy. (18)F-FDOPA metabolic tumor volumes (MTV) as well as max and mean standardized uptake values (SUV) within this MTV were obtained. MRI treatment response was assessed at six weeks. The predictive ability of (18)F-FDOPA PET and MRI response assessment were evaluated with regard to progression-free survival (PFS) and overall survival (OS).

July 2014

Immunohistochemical Analysis of a Ruptured Basilar Top Aneurysm Autopsied 22 Years After Embolization with Guglielmi Detachable Coils.

Yuki I, Spitzer D, Guglielmi G, Duckwiler G, Fujimoto M, Takao H, Jahan R, Tateshima S, Murayama Y, Viñuela F.

The authors report on the histologic and immunohistochemical analyses of a cerebral aneurysm embolized with platinum coils and with the longest observation period. A 58-year-old woman presenting with subarachnoid hemorrhage due to ruptured basilar top aneurysm was treated with Guglielmi detachable coils (GDC) 22 years ago. She was the 15th case since the GDC was introduced. After she died of unrelated causes, an autopsy and thorough histologic examination were performed. Gross examination revealed no adhesion between the aneurysm wall and the surrounding brain tissue. Histologic and immunohistochemical analyses demonstrated that the cavity of the aneurysm was filled with homogeneous collagenous fibrous tissue, while the neck was completely covered by a dense collagenous neointima and a smooth muscle cell layer. The unique histologic results of this case may contribute to a better understanding of the long-term evolution of the healing process in intracranial aneurysms successfully treated with the GDC.

Jun 2014

Inferior Vena Cava Filter Retrieval: Effectiveness and Complications of Routine and Advanced Techniques.

Al-Hakim R, Kee ST, Olinger K, Lee EW, Moriarty JM, McWilliams JP.

PURPOSE: To investigate the success and safety of routine versus advanced inferior vena cava (IVC) filter retrieval techniques. MATERIALS AND METHODS: A retrospective review was performed of patients who underwent IVC filter placement and/or a retrieval attempt over a 10-year period. Retrieval technique(s), preretrieval computed tomography, preretrieval venography, and clinical/imaging follow-up for 30 days after retrieval were analyzed. Mean filter dwell time was 134 days (range, 0-2,475 d).

Jun 2014

WFPI Virtual Communications Centre: a Hive of E-mail Activity.

Andronikou S, Dehaye A, Boechat MI.

The World Federation of Pediatric Imaging (WFPI) functions in a virtual space spanning six continents to coordinate activities for its worldwide membership. A distance of 9,400 km and a time difference of 9 h separate the current president, who resides in Los Angeles (USA), and the general manager, who lives in southwest France.

Jun 2014

Another International Imaging Society-to What End? : The World Federation of Pediatric Imaging: One Voice, a Common Message, a Unified Network.

Dehaye A, Cain T, Boechat MI.

The foundations of the World Federation of Pediatric Imaging were laid during the first International Symposium on Pediatric Imaging held in Rio de Janeiro in 2009. Pediatric radiologists from all over the world came together to share their knowledge with colleagues. A global movement was born to better integrate the existing international societies of pediatric imaging with regional and local organizations and to unite voices advocating for universal access to appropriate pediatric imaging. Created in 2011, the World Federation of Pediatric Imaging (WFPI) works to unite pediatric imaging organizations to form one voice, a common message, and a unified network in addressing the global challenges of pediatric imaging.

Jun 2014

Educational Interventions to Improve Screening Mammography Interpretation: a Randomized Controlled Trial.

Geller BM, Bogart A, Carney PA, Sickles EA, Smith R, Monsees B, Bassett LW, Buist DM, Kerlikowske K, Onega T, Yankaskas BC, Haneuse S, Hill D, Wallis MG, Miglioretti D.

OBJECTIVE: The objective of our study was to conduct a randomized controlled trial of educational interventions that were created to improve performance of screening mammography interpretation. MATERIALS AND METHODS: We randomly assigned physicians who interpret mammography to one of three groups: self-paced DVD, live expert-led educational seminar, or control. The DVD and seminar interventions used mammography cases of varying difficulty and provided associated teaching points. Interpretive performance was compared using a pretest-posttest design. Sensitivity, specificity, and positive predictive value (PPV) were calculated relative to two outcomes: cancer status and consensus of three experts about recall. The performance measures for each group were compared using logistic regression adjusting for pretest performance.

Jun 2014

World Federation of Pediatric Imaging (WFPI) Volunteer Outreach Through Tele-reading: the Pilot Project in South Africa.

Griggs R, Andronikou S, Nell R, O'Connell N, Dehaye A, Boechat MI.

BACKGROUND: Shortages in radiology services are estimated to affect 3.5-4.7 billion people worldwide. Teleradiology is a potential means of alleviating this shortage. OBJECTIVE: This paper examines the practicality and sustainability of a pilot pediatric teleradiology project at the Khayelitsha District Hospital in sub-Saharan Africa. We analyze how this World Federation of Pediatric Imaging (WFPI) program fares against the global challenges described in the current literature facing these practice types. MATERIALS AND METHODS: A teleradiology pilot was developed to provide coverage to the Khayelitsha District Hospital after the district pediatrician requested assistance in interpreting radiographs. This program utilized a network of WFPI volunteer pediatric radiologists, direct JPEG conversion of digital radiographic images, and an e-mail delivery system of images, referral requests and teleradiology opinion. Data were collected retrospectively from referral cards and JPEG images of radiographs, as well as from the volunteer officer database.

Jun 2014

Suppression of Stent-induced Tissue Hyperplasia in Rats by Using Small Interfering RNA to Target Matrix Metalloproteinase-9.

Kim EY, Shin JH, Song HY, Kim JH, Lee EW, Kim WJ, Shin DH, Lee H.

Background and study aims: We evaluated the efficacy of small interfering RNA (siRNA) in targeting matrix metalloproteinase (MMP-9) to suppress stent-induced tissue hyperplasia in a rat esophageal model. Methods: The silencing effect of the candidate siRNA (termed (MMP-9 siRNA) was evaluated in 9 L rat glial cells. Four groups of rats (n = 10, each group) were used: Eso-S, stent insertion only, comparison; Eso-R, stent insertion plus treatment with MMP-9 siRNA complexed with Chol-R9 for delivery, experimental; Eso-P, stent insertion plus treatment with pCMV-luc complexed with Chol-R9, for confirmation of Chol-R9 delivery effect; and Eso-N, no stent insertion and no treatment, controls. All rats were sacrificed at 3 weeks. The therapeutic efficacy of the MMP-9 siRNA/Chol-R9 complex was assessed. Results: The most potent MMP-9 siRNA was selected. Compared with the Eso-S group, the Eso-R group showed significantly less tissue hyperplasia with a lower percentage of granulation tissue and smaller granulation tissue area, and also significantly lower MMP-9 level. Conclusions: MMP-9 siRNA/Chol-R9 is effective for inhibiting stent-induced tissue hyperplasia in a rat esophageal model.

Jun 2014

Velocity Encoding with the Slice Select Refocusing Gradient for Faster Imaging and Reduced Chemical Shift-Induced Phase Errors.

Middione MJ, Thompson RB, Ennis DB.

PURPOSE: To investigate a novel phase-contrast MRI velocity-encoding technique for faster imaging and reduced chemical shift-induced phase errors. METHODS: Velocity encoding with the slice select refocusing gradient achieves the target gradient moment by time shifting the refocusing gradient, which enables the use of the minimum in-phase echo time (TE) for faster imaging and reduced chemical shift-induced phase errors. Net forward flow was compared in 10 healthy subjects (N = 10) within the ascending aorta (aAo), main pulmonary artery (PA), and right/left pulmonary arteries (RPA/LPA) using conventional flow compensated and flow encoded (401 Hz/px and TE = 3.08 ms) and slice select refocused gradient velocity encoding (814 Hz/px and TE = 2.46 ms) at 3 T.

Jun 2014

Deferred Use of Bevacizumab for Recurrent Glioblastoma is Not Associated with Diminished Efficacy.

Piccioni DE, Selfridge J, Mody RR, Chowdhury R, Li S, Lalezari S, Wawrzynski J, Quan J, Zurayk M, Chou AP, Sanchez DE, Liau LM, Ellingson BM, Pope WB, Nghiemphu PL, Green RM, Wang HJ, Yong WH, Elashoff R, Cloughesy TF, Lai A.

BACKGROUND: The optimal timing to initiate bevacizumab (BV) therapy for recurrent glioblastoma (GBM) is currently unclear. To address this issue, we examined progression-free survival (PFS) and survival time (ST) in a large retrospective cohort of GBM patients treated with BV at different recurrences. METHODS: We identified 468 primary GBM patients who underwent biopsy or surgery followed by radiation therapy and temozolomide (RT/TMZ), and then received BV. PFS and ST were compared between patients stratified by the recurrence that BV was initiated (upfront, first recurrence, second recurrence, or 3+ recurrences). We also examined the effect on PFS and ST of the addition of chemotherapy to BV. In a larger cohort of GBM patients, we determined overall treatment continuation rates at each recurrence and identified variables predictive of inability to continue treatment.

Jun 2014

Successful Treatment of Extensive Cerebral Venous Sinus Thrombosis Using a Combined Approach with Penumbra Aspiration System and Solitaire FR Retrieval Device.

Raychev R, Tateshima S, Rastogi S, Balgude A, Yafeh B, Saver JL, Vespa PM, Buitrago M, Duckwiler G.

We present a young woman with rapidly progressive neurologic decline in the setting of malignant cerebral edema due to extensive superior sagittal sinus thrombosis and cortical venous thrombosis despite intravenous heparin administration. Complete revascularization of the occluded sinus was achieved using suction thrombectomy with the 5 max Penumbra catheter in combination with the Solitaire FR clot retrieval device. The successful endovascular treatment halted the progression of her cerebral edema, and the patient eventually had an excellent recovery after prolonged intensive medical therapy. To our knowledge, this is the first reported case describing such a combined mechanical approach for cerebral venous sinus thrombosis. The clot retrieval properties of the Solitaire device combined with direct aspiration via the newest generation Penumbra catheters may allow more rapid, safe and efficient revascularization than all previously reported endovascular treatments for this potentially devastating condition.

Jun 2014

Patients with Nodular Regenerative Hyperplasia Should be Considered for Hepatocellular Carcinoma Screening.

Sood A, Cox GA 2nd, McWilliams JP, Wang HL, Saab S.

The incidence of hepatocellular carcinoma (HCC) appears to be increasing across the globe. Well-established protocols for screening are available, and the most common underlying liver problem associated with the development of HCC is cirrhosis. However, with few exceptions, patients without cirrhosis are generally not screened for HCC. Nodular regenerative hyperplasia (NRH) is not associated with the development of significant fibrosis or impaired liver synthetic function. The major clinical impact of NRH appears to be in the development of portal hypertension. Patients with NRH are also not recommended to undergo routine screening for the development of HCC. This report describes a case of a 44-year-old woman with NRH found to have de novo HCC. Emerging evidence suggest a possible pathogenetic relationship between NRH and HCC. The case described here and our review of the published work suggests that additional studies regarding the epidemiological association between NRH and HCC may change the current notion that NRH is not a premalignant lesion, and further studies assessing the utility of routine screening of NRH patients for HCC should be considered.

Jun 2014

Clear Cell Renal Cell Carcinoma: Multiphasic MDCT Enhancement can Predict the Loss of Chromosome 8p.

Young JR, Margolis D, Sauk S, Pantuck AJ, Sayre J, Young JA, Hsu M, Raman SS.

PURPOSE: To investigate whether imaging features on multiphasic multidetector computed tomography (MDCT) can predict the loss of chromosome 8p in clear cell renal cell carcinomas (RCCs), a cytogenetic abnormality associated with a higher tumor grade and greater risk of recurrence. METHODS: With IRB approval for this HIPAA-compliant retrospective study, we queried our institution's pathology database to derive all histologically proven cases of clear cell RCC with preoperative multiphasic MDCT with as many as four phases (unenhanced, corticomedullary, nephrographic, and excretory) from January 2000 to July 2010. Of 170 clear cell RCCs with preoperative multiphasic MDCT, 105 clear cell RCCs, representing 98 unique patients, had karyotypes of the resected specimens. Lesions were evaluated for magnitude and pattern of enhancement, contour, neovascularity, calcifications, and size.

May 2014

Multiparametric MRI Identifies and Stratifies Prostate Cancer Lesions: Implications for Targeting Intraprostatic Targets.

Anderson ES, Margolis DJ, Mesko S, Banerjee R, Wang PC, Demanes DJ, Kupelian P, Kamrava M.

PURPOSE: To assess the ability of multiparametric (mp) MRI (mp-MRI) to identify, stratify, and localize biopsy-proven prostate cancer lesions in a risk-stratified patient population. METHODS AND MATERIALS: We retrospectively analyzed 57 patients who had mp-MRI and core needle biopsy during diagnostic prostate cancer evaluation. The MRI sequences were scored for suspicion of cancer with a previously described system. Distributions of mp-MRI scores were compared across National Comprehensive Cancer Network prostate cancer risk groups. The mp-MRI-identified lesions were compared with the location of positive core needle biopsies to assess mp-MRI localization of true lesions.

May 2014

The Pituitary Stalk Effect: Is It a Passing Phenomenon?

Bergsneider M, Mirsadraei L, Yong WH, Salamon N, Linetsky M, Wang MB, McArthur DL, Heaney AP.

Most patients with large pituitary tumors do not exhibit hyperprolactinemia as a result of pituitary lactotroph disinhibition (stalk effect). Studies have demonstrated that increased intrasellar pressure is associated with both "stalk effect" hyperprolactinemia and pituitary insufficiency. Our primary hypothesis was that, despite continued disinhibition, lactotroph failure is responsible for normoprolactinemia in patients with large macroadenomas. As a corollary, we proposed that the hyperprolactinemia phase, which presumably would precede the insufficiency/normoprolactinemic state, would more likely be discovered in premenopausal females and go unnoticed in males. Prospective, consecutive surgical series of 98 patients of clinically nonfunctional pituitary adenomas. Lactotroph insufficiency was inferred by the coexistence of insufficiency in another pituitary axis. The existence of pre-operative lactotroph disinhibition was inferred based on comparison of pre- versus post-operative prolactin levels. 87 % of patients with tumor size >20 mm and normoprolactinemia had pituitary insufficiency. Pre-operative prolactin in patients with pituitary insufficiency were lower than those with intact pituitary function. Prolactin levels dropped in nearly all patients, including patients with normoprolactinemia pre-operatively. Premenopausal women had smaller tumors and higher pre-operative prolactin levels compared to males. No premenopausal female exhibited evidence of pituitary insufficiency. Our study provides suggestive evidence that the "stalk effect" pathophysiology is the norm rather than the exception, and that the finding of normoprolactinemia in a patient with a large macroadenoma is likely a consequence of lactotroph insufficiency. In males, the hyperprolactinemia window is more likely to be missed clinically due to an absence of prolactin-related symptoms.

May 2014

ACR Appropriateness Criteria Post-Treatment Follow-Up of Renal Cell Carcinoma.

Casalino DD, Remer EM, Bishoff JT, Coursey CA, Dighe M, Harvin HJ, Heilbrun ME, Majd M, Nikolaidis P, Preminger GM, Raman SS, Sheth S, Vikram R, Weinfeld RM.

Although localized renal cell carcinoma can be effectively treated by surgery or ablative therapies, local or distant metastatic recurrence after treatment is not uncommon. Because recurrent disease can be effectively treated, patient surveillance after treatment of renal cell carcinoma is very important. Surveillance protocols are generally based on the primary tumor's size, stage, and nuclear grade at the time of resection, as well as patterns of tumor recurrence, including where and when metastases occur. Various imaging modalities may be used in the evaluation of these patients. Literature on the indications and usefulness of these radiologic studies is reviewed. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

May 2014

The Nature of Change.

Enzmann DR, Feinberg DT.

There is little doubt that health care is facing change. The conventional view of change, based on evolution, is that it is slow, gradual, and generally an evenly paced system change. Unfortunately, it is much more uneven, being burstlike, unpredictable, and, in fact, steplike. This pattern is called punctuated equilibrium, which is well illustrated by the metaphorical picture of the Devil's Staircase. These features call for a reassessment of how to cope with change. In addition to detecting change, responding to it and preparing for it require some understanding of the role of experimentation because the evolution algorithm is simple: experimentation, selection, and replication. Experimentation in radiology forms a continuum ranging from modifying traits to developing variants of diagnostic, interventional, and even new integrated services. We often describe experiments by relating their motives (ie, adaptation and innovation), but complex systems see only experiments available for selection. Experiments generating new services and business models are the important ones because they create the "subspecies" of radiology, which offers a robust set of options capable of withstanding new health care selection forces. Experimentation and selection are the prerequisites of replication (i.e., survival). It behooves radiology to combine and concatenate diversified, reactive, and innovative experiments to explore adjacent domains to expand its set of options. Just as in Darwinian evolution, major changes on the health care landscape will be at the specialty, ie, species and subspecies levels, rather than at the individual specialty trait level. Radiology needs a strong set of "subspecies" to succeed in selection to enhance evolution and allow replication.

May 2014

Temporal Correlation between Wall Shear Stress and In-Stent Stenosis after Wingspan Stent in Swine Model.

Fujimoto M, Takao H, Suzuki T, Shobayashi Y, Mayor F, Tateshima S, Yamamoto M, Murayama Y, Viñuela F.

BACKGROUND AND PURPOSE: A recent randomized clinical trial on intracranial atherosclerosis was discontinued because of the higher frequency of stroke and death in the angioplasty and stent placement group than in the medical treatment group. An in-depth understanding of the relationship between biologic responses and flow dynamics is still required to identify the current limitations of intracranial stent placement. MATERIALS AND METHODS: Five Wingspan stents were deployed in tapered swine ascending pharyngeal arteries. Temporal wall shear stress distributions and in-stent stenosis were evaluated at days 0, 7, 14, and 28 after stent placement. The physiologic role of wall shear stress was analyzed regarding its correlation with in-stent stenosis.

May 2014

Diagnostic Performance Comparison of the Chartis System and High-Resolution Computerized Tomography Fissure Analysis for Planning Endoscopic Lung Volume Reduction.

Gompelmann D, Eberhardt R, Slebos DJ, Brown MS, Abtin F, Kim HJ, Holmes-Higgin D, Radhakrishnan S, Herth FJ, Goldin J.

BACKGROUND AND OBJECTIVE: Endobronchial valve (EBV) therapy is optimized in patients who demonstrate little or no collateral ventilation (CV). The accuracy of the Chartis System and visual assessment of high-resolution computerized tomography (HRCT) fissure completeness by a core radiology laboratory for classifying CV status was compared by evaluating the relationship of each method with target lobe volume reduction (TLVR) after EBV placement. METHODS: Retrospective HRCT fissure analysis of a study population who underwent catheter-based measurement of CV followed by complete occlusion of the targeted lobe by EBV. Accuracy, sensitivity, specificity, positive predictive value and negative predictive value of the HRCT fissure analysis and the catheter-based measurement of CV for predicting TLVR was determined.

May 2014

ACR Appropriateness Criteria® Hemoptysis.

Ketai LH, Mohammed TL, Kirsch J, Kanne JP, Chung JH, Donnelly EF, Ginsburg ME, Heitkamp DE, Henry TS, Kazerooni EA, Lorenz JM, McComb BL, Ravenel JG, Saleh AG, Shah RD, Steiner RM, Suh RD; Expert Panel on Thoracic Imaging.

Although hemoptysis is often self-limited and benign in origin, it can be an indicator of serious disease including bronchiectasis, granulomatous infection, and malignancy. Hemoptysis severity can be graded on the basis of the quantity of expectorated blood: <30 mL of hemoptysis as minor, 30 to 300 mL as moderate to severe (major), and >300 to 400 mL in 24 hours as massive. Among patients with hemoptysis, chest radiographs are often abnormal and can guide evaluation. The overall risk for malignancy in patients with normal radiographs is low but may be as much as 5% to 10% in patients with >30 mL of hemoptysis and those who are above 40 years of age and have significant smoking history. A combination of negative computed tomography and bronchoscopy results predicts a very low likelihood of lung malignancy diagnosis over medium-term follow-up (2 to 3 y). Bronchial and nonbronchial systemic arteries are much more frequent sources of hemoptysis than pulmonary arteries. Major or massive hemoptysis can usually be stopped acutely by bronchial arterial embolization. Recurrences, however, are common and often require repeat embolization. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

May 2014

Tagging of Cardiac Magnetic Resonance Images in the Polar Coordinate System: Physical Principles and Practical Implementation.

Nasiraei-Moghaddam A, Finn JP.

PURPOSE: In current magnetic resonance practice, myocardial tagging is implemented by laying down a rectilinear presaturation grid over the heart. Although both the geometry and the deformation of the heart are better described in the polar coordinate system, practical methods for laying down polar grids have been elusive. The theory and implementation of high-density tagging in the polar coordinate system is described in this study. METHODS: Tagging sequences for generating high-density tagging patterns in both radial and circular directions have been developed. The approach, theoretical basis, and experimental results of the suggested sequences for efficient polar tagging are described in this article.

May 2014

A Novel Fast Helical 4D-CT Acquisition Technique to Generate Low-Noise Sorting Artifact-Free Images at User-Selected Breathing Phases.

Thomas D, Lamb J, White B, Jani S, Gaudio S, Lee P, Ruan D, McNitt-Gray M, Low D.

PURPOSE: To develop a novel 4-dimensional computed tomography (4D-CT) technique that exploits standard fast helical acquisition, a simultaneous breathing surrogate measurement, deformable image registration, and a breathing motion model to remove sorting artifacts. METHODS AND MATERIALS: Ten patients were imaged under free-breathing conditions 25 successive times in alternating directions with a 64-slice CT scanner using a low-dose fast helical protocol. An abdominal bellows was used as a breathing surrogate. Deformable registration was used to register the first image (defined as the reference image) to the subsequent 24 segmented images. Voxel-specific motion model parameters were determined using a breathing motion model. The tissue locations predicted by the motion model in the 25 images were compared against the deformably registered tissue locations, allowing a model prediction error to be evaluated. A low-noise image was created by averaging the 25 images deformed to the first image geometry, reducing statistical image noise by a factor of 5. The motion model was used to deform the low-noise reference image to any user-selected breathing phase. A voxel-specific correction was applied to correct the Hounsfield units for lung parenchyma density as a function of lung air filling.

May 2014

Carotid Artery Plaque Morphology and Composition in Relation to Incident Cardiovascular Events: The Multi-Ethnic Study of Atherosclerosis (MESA).

Zavodni AE, Wasserman BA, McClelland RL, Gomes AS, Folsom AR, Polak JF, Lima JA, Bluemke DA.

Purpose To determine if carotid plaque morphology and composition with magnetic resonance (MR) imaging can be used to identify asymptomatic subjects at risk for cardiovascular events. Materials and Methods Institutional review boards at each site approved the study, and all sites were Health Insurance Portability and Accountability Act (HIPAA) compliant. A total of 946 participants in the Multi-Ethnic Study of Atherosclerosis (MESA) were evaluated with MR imaging and ultrasonography (US). MR imaging was used to define carotid plaque composition and remodeling index (wall area divided by the sum of wall area and lumen area), while US was used to assess carotid wall thickness. Incident cardiovascular events, including myocardial infarction, resuscitated cardiac arrest, angina, stroke, and death, were ascertained for an average of 5.5 years. Multivariable Cox proportional hazards models, C statistics, and net reclassification improvement (NRI) for event prediction were determined. Results Cardiovascular events occurred in 59 (6%) of participants. Carotid IMT as well as MR imaging remodeling index, lipid core, and calcium in the internal carotid artery were significant predictors of events in univariate analysis (P < .001 for all). For traditional risk factors, the C statistic for event prediction was 0.696. For MR imaging remodeling index and lipid core, the C statistic was 0.734 and the NRI was 7.4% and 15.8% for participants with and those without cardiovascular events, respectively (P = .02). The NRI for US IMT in addition to traditional risk factors was not significant. Conclusion The identification of vulnerable plaque characteristics with MR imaging aids in cardiovascular disease prediction and improves the reclassification of baseline cardiovascular risk.

Apr 2014

Diastolic Function Assessed from Tagged MRI Predicts Heart Failure and Atrial Fibrillation Over an 8-year Follow-up Period: the Multi-ethnic Study of Atherosclerosis.

Ambale-Venkatesh B, Armstrong AC, Liu CY, Donekal S, Yoneyama K, Wu CO, Gomes AS, Hundley GW, Bluemke DA, Lima JA.

OBJECTIVES: The strain relaxation index (SRI), a novel diastolic functional parameter derived from tagged magnetic resonance imaging (MRI), is used to assess myocardial deformation during left ventricular relaxation. We investigated whether diastolic function indexed by SRI predicts heart failure (HF) and atrial fibrillation (AF) over an 8-year follow-up. METHODS: As a part of the multi-ethnic study of atherosclerosis, 1544 participants free of known cardiovascular disease (CVD) underwent tagged MRI in 2000-02. Harmonic phase analysis was used to compute circumferential strain. Standard parameters, early diastolic strain rate (EDSR) and the peak torsion recoil rate were calculated. An SRI was calculated as difference between post-systolic and systolic times of the strain peaks, divided by the EDSR peak. It was normalized by the total interval of relaxation. Over an 8-year follow-up period, we defined AF (n = 57) or HF (n = 36) as combined (n = 80) end-points. Cox regression assessed the ability of SRI to predict events adjusted for risk factors and markers of subclinical disease. Integrated discrimination index (IDI) and net reclassification index (NRI) of SRI, compared with conventional indices, were also assessed.

Apr 2014

ACR Appropriateness Criteria Blunt Chest Trauma.

Chung JH, Cox CW, Mohammed TL, Kirsch J, Brown K, Dyer DS, Ginsburg ME, Heitkamp DE, Kanne JP, Kazerooni EA, Ketai LH, Ravenel JG, Saleh AG, Shah RD, Steiner RM, Suh RD.

Imaging is paramount in the setting of blunt trauma and is now the standard of care at any trauma center. Although anteroposterior radiography has inherent limitations, the ability to acquire a radiograph in the trauma bay with little interruption in clinical survey, monitoring, and treatment, as well as radiography's accepted role in screening for traumatic aortic injury, supports the routine use of chest radiography. Chest CT or CT angiography is the gold-standard routine imaging modality for detecting thoracic injuries caused by blunt trauma. There is disagreement on whether routine chest CT is necessary in all patients with histories of blunt trauma. Ultimately, the frequency and timing of CT chest imaging should be site specific and should depend on the local resources of the trauma center as well as patient status. Ultrasound may be beneficial in the detection of pneumothorax, hemothorax, and pericardial hemorrhage; transesophageal echocardiography is a first-line imaging tool in the setting of suspected cardiac injury. In the blunt trauma setting, MRI and nuclear medicine likely play no role in the acute setting, although these modalities may be helpful as problem-solving tools after initial assessment. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Apr 2014

Recurrent Glioblastoma Treated with Bevacizumab: Contrast-enhanced T1-weighted Subtraction Maps Improve Tumor Delineation and Aid Prediction of Survival in a Multicenter Clinical Trial.

Ellingson BM, Kim HJ, Woodworth DC, Pope WB, Cloughesy JN, Harris RJ, Lai A, Nghiemphu PL, Cloughesy TF.

Purpose To compare the capability to aid prediction of clinical outcome measures, including progression-free survival (PFS) and overall survival (OS), between volumetric estimates from contrast material-enhanced (CE) T1-weighted subtraction maps and traditional segmentation in a randomized multicenter clinical trial of recurrent glioblastoma (GBM) patients treated with bevacizumab. Materials and Methods All patients participating in this study signed institutional review board-approved informed consent at their respective institutions prior to enrolling in the multicenter clinical trial. One-hundred sixty patients with recurrent GBM enrolled as part of a HIPAA-compliant, multicenter clinical trial (AVF3708 g, BRAIN trial). Contrast-enhancing tumor volumes and change in volumes as a response to therapy were quantified by using either conventional segmentation or CE T1-weighted subtraction maps created by voxel-by-voxel subtraction of intensity-normalized nonenhanced T1-weighted images from CE T1-weighted images. These volumes were then tested as predictors of PFS and OS by using log-rank univariate analysis, the multivariate Cox proportional hazards regression model, and receiver operating characteristic analysis. Results Use of CE T1-weighted subtraction maps qualitatively improved visualization and improved quantification of tumor volume after bevacizumab treatment. Significant trends between the volume of tumor and change in tumor volume after therapy on CE T1-weighted subtraction maps were found for both PFS and OS (pretreatment volume < 15 cm(3), P < .003; posttreatment volume < 7.5 cm(3), P < .05; percentage change in volume > 25%, P = .004 for PFS and P = .053 for OS). CE T1-weighted subtraction maps were significantly better at aiding prediction of 6-month PFS and 12-month OS compared with conventional segmentation by using receiver operating characteristic analysis (P < .05). Conclusion Use of CE T1-weighted subtraction maps improved visualization and aided better prediction of patient survival in recurrent GBM treated with bevacizumab compared with conventional segmentation of CE T1-weighted images. ©RSNA, 2013 Clinical trial registration no. NCT00345163 Online supplemental material is available for this article.

Apr 2014

Vascular Plug-assisted Retrograde Transvenous Obliteration of Portosystemic Shunts for Refractory Hepatic Encephalopathy: a Case Report.

Park JK, Cho SK, Kee S, Lee EW.

While balloon-assisted retrograde transvenous obliteration (BRTO) has been used for two decades in Asia for the management of gastric variceal bleeding, it is still an emerging therapy elsewhere. Given the shunt closure brought about by the procedure, BRTO has also been used for the management of portosystemic encephalopathy with promising results. Modified versions of BRTO have been developed, including plug-assisted retrograde transvenous obliteration (PARTO), where a vascular plug is deployed within a portosystemic shunt. To our knowledge, we present the first North American case of PARTO in the setting of a large splenorenal shunt for the management of portosystemic encephalopathy.

Apr 2014

Value of Targeted Prostate Biopsy Using Magnetic Resonance-Ultrasound Fusion in Men with Prior Negative Biopsy and Elevated Prostate-specific Antigen.

Sonn GA, Chang E, Natarajan S, Margolis DJ, Macairan M, Lieu P, Huang J, Dorey FJ, Reiter RE, Marks LS.

BACKGROUND: Conventional biopsy fails to detect the presence of some prostate cancers (PCas). Men with a prior negative biopsy but persistently elevated prostate-specific antigen (PSA) pose a diagnostic dilemma, as some harbor elusive cancer. OBJECTIVE: To determine whether use of magnetic resonance-ultrasound (MR-US) fusion biopsy results in improved detection of PCa compared to repeat conventional biopsy. DESIGN, SETTING, AND PARTICIPANTS: In a consecutive-case series, 105 subjects with prior negative biopsy and elevated PSA values underwent multiparametric magnetic resonance imaging (MRI) and fusion biopsy in an outpatient setting. INTERVENTION: Suspicious areas on multiparametric MRI were delineated and graded by a radiologist; MR-US fusion biopsy was performed by a urologist using the Artemis device; targeted and systematic biopsies were obtained regardless of MRI result. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Detection rates of all PCa and clinically significant PCa (Gleason ≥3+4 or Gleason 6 with maximal cancer core length ≥4 mm) were determined. The yield of targeted biopsy was compared to systematic biopsy. The ability of an MRI grading system to predict clinically significant cancer was investigated. Stepwise multivariate logistic regression analysis was performed to determine predictors of significant cancer on biopsy.

Mar 2014

C-terminally Truncated form of αB-crystallin is Associated with IDH1 R132H Mutation in Anaplastic Astrocytoma.

Avliyakulov NK, Rajavel KS, Le KM, Guo L, Mirsadraei L, Yong WH, Liau LM, Li S, Lai A, Nghiemphu PL, Cloughesy TF, Linetsky M, Haykinson MJ, Pope WB.

Malignant gliomas are the most common human primary brain tumors. Point mutation of amino acid arginine 132 to histidine (R132H) in the IDH1 protein leads to an enzymatic gain-of-function and is thought to promote gliomagenesis. Little is known about the downstream effects of the IDH1 mutation on protein expression and how and whether changes in protein expression are involved in tumor formation or propagation. In the current study, we used 2D DIGE (difference gel electrophoresis) and mass spectrometry to analyze differences in protein expression between IDH1(R132H) mutant and wild type anaplastic (grade III) astrocytoma from human brain cancer tissues. We show that expression levels of many proteins are altered in IDH1(R132H) mutant anaplastic astrocytoma. Some of the most over-expressed proteins in the mutants include several forms of αB-crystallin, a small heat-shock and anti-apoptotic protein. αB-crystallin proteins are elevated up to 22-fold in IDH1(R132H) mutant tumors, and αB-crystallin expression appears to be controlled at the post-translational level. We identified the most abundant form of αB-crystallin as a low molecular weight species that is C-terminally truncated. We also found that overexpression of αB-crystallin can be induced by transfecting U251 human glioblastoma cell lines with the IDH1(R132H) mutation. In conclusion, the association of a C-terminally truncated form of αB-crystallin protein with the IDH1(R132H) mutation is a novel finding that could impact apoptosis and stress response in IDH1 mutant glioma.

Mar 2014

Interstitial Fibrosis, Left Ventricular Remodeling, and Myocardial Mechanical Behavior in a Population-Based Multiethnic Cohort: The Multi-Ethnic Study of Atherosclerosis (MESA) Study.

Donekal S, Venkatesh BA, Liu YC, Liu CY, Yoneyama K, Wu CO, Nacif M, Gomes AS, Hundley WG, Bluemke DA, Lima JA.

BACKGROUND: Tagged cardiac magnetic resonance provides detailed information on regional myocardial function and mechanical behavior. T1 mapping by cardiac magnetic resonance allows noninvasive quantification of myocardial extracellular expansion (ECE), which has been related to interstitial fibrosis in previous clinical and subclinical studies. We assessed sex-associated differences in the relation of ECE to left ventricular (LV) remodeling and myocardial systolic and diastolic deformation in a large community-based multiethnic population. METHODS AND RESULTS: Midventricular midwall peak circumferential shortening and early diastolic strain rate and LV torsion and torsional recoil rate were determined using cardiac magnetic resonance tagging. Midventricular short-axis T1 maps were acquired in the same examination pre- and postcontrast injection using Modified Look-Locker Inversion-Recovery sequence. Multivariable linear regression (estimated regression coefficient, B) was used to adjust for risk factors and subclinical disease measures.

Mar 2014

Stress Fracture of the Scapula in a Professional Baseball Pitcher: Case Report and Review of the Literature.

Levine BD, Resnick DL.

We report a case of a 26-year-old, right-handed professional baseball pitcher who presented with gradually worsening right shoulder pain. Initial magnetic resonance imaging and computed tomography demonstrated a stress fracture involving the posterior aspect of the scapula at the junction between the scapular neck and body. After a period of rest, follow-up magnetic resonance imaging and computed tomography performed 3 1/2 weeks later demonstrated ongoing healing of the stress fracture.

Mar 2014

Serial Alberta Stroke Program Early CT Score From Baseline to 24 Hours in Solitaire Flow Restoration With the Intention for Thrombectomy Study: A Novel Surrogate End Point for Revascularization in Acute Stroke.

Liebeskind DS, Jahan R, Nogueira RG, Jovin TG, Lutsep HL, Saver JL; SWIFT Investigators.

BACKGROUND & PURPOSE: The Alberta Stroke Program Early CT Score (ASPECTS) on baseline imaging is an established predictor of acute ischemic stroke outcomes. We analyzed change on serial ASPECTS at baseline and 24-hour imaging in the Solitaire Flow Restoration with the Intention for Thrombectomy (SWIFT) study to determine prognostic value and to identify subgroups with extensive injury after intervention. METHODS: ASPECTS at baseline and 24 hours was independently scored in all anterior circulation SWIFT cases, blinded to all other trial data. ASPECTS at baseline, at 24 hours, and serial changes were analyzed with univariate and multivariate approaches.

Mar 2014

Distinct Trends of Pulsatility Found at the Necks of Ruptured and Unruptured Aneurysms.

Patti J, Viñuela F, Chien A.

BACKGROUND: Aneurysm hemodynamics has been shown to be an important factor in aneurysm growth and rupture. Although pulsatility is essential for blood flow and vascular wall function, studies of pulsatile flow properties in brain aneurysm disease are limited. OBJECTIVE: To investigate differences in pulsatility within a group of ruptured and unruptured aneurysms by implementing patient-specific pulsatile flow simulation. METHODS: 41 of 311 internal carotid artery aneurysms were selected from an aneurysm database (29 unruptured and 12 ruptured) and used for patient-specific hemodynamic simulations of pulsatile flow. Flow pulsatility changes in ruptured and unruptured groups were analyzed by comparing different components of blood flow. Pulsatility index (PI) was used to quantify the pulsatility of blood flow in each group at the aneurysm neck, body, dome, and parent artery.

Mar 2014

Accelerating Dynamic Magnetic Resonance Imaging (MRI) for Lung Tumor Tracking Based on Low-Rank Decomposition in the Spatial-Temporal Domain: a Feasibility Study Based on Simulation and Preliminary Prospective Undersampled MRI.

Sarma M, Hu P, Rapacchi S, Ennis D, Thomas A, Lee P, Kupelian P, Sheng K.

PURPOSE: To evaluate a low-rank decomposition method to reconstruct down-sampled k-space data for the purpose of tumor tracking. METHODS AND MATERIALS: Seven retrospective lung cancer patients were included in the simulation study. The fully-sampled k-space data were first generated from existing 2-dimensional dynamic MR images and then down-sampled by 5 x -20 x before reconstruction using a Cartesian undersampling mask. Two methods, a low-rank decomposition method using combined dynamic MR images (k-t SLR based on sparsity and low-rank penalties) and a total variation (TV) method using individual dynamic MR frames, were used to reconstruct images. The tumor trajectories were derived on the basis of autosegmentation of the resultant images. To further test its feasibility, k-t SLR was used to reconstruct prospective data of a healthy subject. An undersampled balanced steady-state free precession sequence with the same undersampling mask was used to acquire the imaging data.

Mar 2014

Onyx Embolization of Anterior Condylar Confluence Dural Arteriovenous Fistula.

Takemoto K, Tateshima S, Rastogi S, Gonzalez N, Jahan R, Duckwiler G, Viñuela F.

The anterior condylar confluence (ACC) is a small complex venous structure located medial to the jugular vein and adjacent to the hypoglossal canal. To our knowledge, this is the first report of transvenous Onyx embolization for ACC dural arteriovenous fistula (DAVF). Three patients with ACC DAVF were treated using the Onyx liquid embolic agent with or without detachable coils. Complete angiographic obliteration of the fistulas was achieved in all cases without permanent lower cranial neuropathy. This report suggests that the controlled penetration of Onyx is advantageous in order to obliterate ACC DAVFs with a small amount of embolic material.

Mar 2014

Increased Sensitivity to Radiochemotherapy in IDH1 Mutant Glioblastoma as Demonstrated by Serial Quantitative MR Volumetry.

Tran AN, Lai A, Li S, Pope WB, Teixeira S, Harris RJ, Woodworth DC, Nghiemphu PL, Cloughesy TF, Ellingson BM.

BACKGROUND: Isocitrate dehydrogenase 1 (IDH1) mutations have been linked to favorable outcomes in patients with glioblastoma multiforme (GBM). Recent in vitro experiments suggest that IDH1 mutation sensitizes tumors to radiation damage. We hypothesized that radiographic treatment response would be significantly different between IDH1 mutant versus wild-type GBMs after radiotherapy (RT) and concurrent temozolomide (TMZ). METHODS: A total of 39 newly diagnosed GBM patients with known IDH1 mutational status (10 IDH1 mutants), who followed standard therapy and had regular post-contrast T1W (T1+C) and T2W/ fluid-attenuated inversion recovery (FLAIR) images in the 6-month period after starting RT, were enrolled. The volume of contrast-enhancing and FLAIR hyperintensity were calculated from each scan. Linear and polynomial regression techniques were used to estimate the rate of change and temporal patterns in tumor volumes.

Feb 2014

Position Statement on Percutaneous Vertebral Augmentation: A Consensus Statement Developed by the Society of Interventional Radiology (SIR), American Association of Neurological Surgeons (AANS) and the Congress of Neurological Surgeons (CNS), American College of Radiology (ACR), American Society of Neuroradiology (ASNR), American Society of Spine Radiology (ASSR), Canadian Interventional Radiology Association (CIRA), and the Society of NeuroInterventional Surgery (SNIS).

Barr JD, Jensen ME, Hirsch JA, McGraw JK, Barr RM, Brook AL, Meyers PM, Munk PL, Murphy KJ, O'Toole JE, Rasmussen PA, Ryken TC, Sanelli PC, Schwartzberg MS, Seidenwurm D, Tutton SM, Zoarski GH, Kuo MD, Rose SC, Cardella JF.

It is the position of the Societies that percutaneous vertebral augmentation (PVA) with the use of vertebroplasty or kyphoplasty is a safe, efficacious, and durable procedure in appropriate patients with symptomatic osteoporotic and neoplastic fractures, when performed in a manner in accordance with published standards. These procedures are offered only when nonoperative medical therapy has not provided adequate pain relief or pain is significantly altering the patient's quality of life. Regarding vertebroplasty, multiple case series and retrospective and prospective nonrandomized studies and, more recently, randomized controlled trials have shown statistically significant improvement in pain and function, particularly ambulation.

Feb 2014

The Morel-Lavallée Lesion: Pathophysiology, Clinical Presentation, Imaging Features, and Treatment Options.

Bonilla-Yoon I, Masih S, Patel DB, White EA, Levine BD, Chow K, Gottsegen CJ, Matcuk GR Jr.

Morel-Lavallée lesions are posttraumatic hemolymphatic collections related to shearing injury and disruption of interfascial planes between subcutaneous soft tissue and muscle. We review the pathophysiology of Morel-Lavallée lesions, clinical presentation, and potential sites of involvement. Magnetic resonance imaging (MRI) is the modality of choice for characterization. We present the MRI classification and highlight the key imaging features that distinguish the different types, focusing on the three most common: seroma, subacute hematoma, and chronic organizing hematoma. Potential mimics of Morel-Lavallée lesions, such as soft tissue sarcoma and hemorrhagic prepatellar bursitis, are compared and contrasted. Treatment options and a management algorithm are also briefly discussed.

Feb 2014

The Role of Magnetic Resonance Imaging in Delineating Clinically Significant Prostate Cancer.

Chamie K, Sonn GA, Finley DS, Tan N, Margolis DJ, Raman SS, Natarajan S, Huang J, Reiter RE.

OBJECTIVE: To determine whether multiparametric magnetic resonance imaging might improve the identification of patients with higher risk disease at diagnosis and thereby reduce the incidence of undergrading or understaging. METHODS: We retrospectively reviewed the clinical records of 115 patients who underwent multiparametric magnetic resonance imaging before radical prostatectomy. We used Epstein's criteria of insignificant disease with and without a magnetic resonance imaging (MRI) parameter (apparent diffusion coefficient) to calculate sensitivity, specificity, as well as negative and positive predictive values [NPV and PPV] across varying definitions of clinically significant cancer based on Gleason grade and tumor volume (0.2 mL, 0.5 mL, and 1.3 mL) on whole-mount prostate specimens. Logistic regression analysis was performed to determine the incremental benefit of MRI in delineating significant cancer.

Feb 2014

Evaluating Patency Rates of an Ultralow-porosity Expanded Polytetrafluoroethylene Covered Stent in the Treatment of Venous Stenosis in Arteriovenous Dialysis Circuits.

Chan MG, Miller FJ, Valji K, Bansal A, Kuo MD.

PURPOSE: To evaluate the efficacy of an ultralow-porosity expanded polytetrafluoroethylene (ePTFE) covered stent in the treatment of autogenous arteriovenous fistula (AVF) and prosthetic arteriovenous graft (AVG) venous outflow stenoses. MATERIALS AND METHODS: Clinical and angiographic outcomes of 20 consecutive patients with arteriovenous dialysis circuits treated with the endoprosthesis were reviewed following institutional review board approval. Patients were followed routinely at 2 months and 6 months after stent placement, or earlier if clinically warranted. The primary endpoint was 2- and 6-month primary treatment area patency. Secondary endpoints included primary circuit patency, primary assisted patency, and secondary patency.

Feb 2014

Assessment of Chronological Effects of Irreversible Electroporation on Hilar Bile Ducts in a Porcine Model.

Choi JW, Lu DS, Osuagwu F, Raman S, Lassman C.

PURPOSE: To evaluate the chronological effects of irreversible electroporation (IRE) on large hilar bile ducts in an in vivo porcine model correlated with computed tomography (CT) cholangiography and histopathology. MATERIALS AND METHODS: Twelve IRE zones were made along hilar bile ducts intraoperatively under ultrasound (US)-guidance in 11 pigs. Paired electrodes were placed either on opposing sides of the bile duct (straddle [STR]) or both on one side of the bile duct (one-sided [OSD]). The shortest electrode-to-duct distance was classified as periductal (≤ 2 mm) or nonperiductal (>2 mm). CT cholangiography and laboratory tests were performed before IRE and again at 2 days, 4 weeks, and 8 weeks after IRE. Degree of bile duct injury were graded as follows: grade 0 = no narrowing; grade 1 = ≤ 50 % duct narrowing; grade 2 = >50 % narrowing without proximal duct dilatation; grade 3 = grade 2 with proximal duct dilatation; and grade 4 = grade 3 with enzyme elevation. Pigs were selected for killing and histopathology at 2 days, 4, and 8 weeks.

Feb 2014

The International Association Study Lung Cancer (IASLC) Strategic Screening Advisory Committee (SSAC) Response to the USPSTF Recommendations.

Field JK, Aberle DR, Altorki N, Baldwin DR, Dresler C, Duffy SW, Goldstraw P, Hirsch FR, Pedersen JH, de Koning HJ, Mulshine JL, Sullivan DC, Tsao MS, Travis WD; International Association for the Study of Lung Cancer Strategic Screening Advisory Committee.

The International Association for the Study of Lung Cancer (IASLC) Strategic Screening Advisory Committee (SSAC) has prepared the following response to the United States Preventive Services Task Force (USPSTF) draft recommendatio on computed tomography (CT) screening with associated systemic review. The Cancer Care Ontario Programme in Evidence-Based Care (CCOP) has also undertaken a similar systemic review. The IASLC SSAC was set up during the World Lung Cancer Conference 2011.

Feb 2014

Behind the Numbers: Decoding Molecular Phenotypes with Radiogenomics-Guiding Principles and Technical Considerations.

Kuo MD, Jamshidi N.

As the field of radiogenomics grows, we can expect improved robustness of the measurement technologies, analysis methods, and, ultimately, the predictive capabilities of radiogenomic maps.

Feb 2014

Overdiagnosis in Low-dose Computed Tomography Screening for Lung Cancer.

Patz EF Jr, Pinsky P, Gatsonis C, Sicks JD, Kramer BS, Tammemägi MC, Chiles C, Black WC, Aberle DR; NLST Overdiagnosis Manuscript Writing Team.

IMPORTANCE Screening for lung cancer has the potential to reduce mortality, but in addition to detecting aggressive tumors, screening will also detect indolent tumors that otherwise may not cause clinical symptoms. These overdiagnosis cases represent an important potential harm of screening because they incur additional cost, anxiety, and morbidity associated with cancer treatment. OBJECTIVE To estimate overdiagnosis in the National Lung Screening Trial (NLST). DESIGN, SETTING, AND PARTICIPANTS We used data from the NLST, a randomized trial comparing screening using low-dose computed tomography (LDCT) vs chest radiography (CXR) among 53 452 persons at high risk for lung cancer observed for 6.4 years, to estimate the excess number of lung cancers in the LDCT arm of the NLST compared with the CXR arm. MAIN OUTCOMES AND MEASURES We calculated 2 measures of overdiagnosis: the probability that a lung cancer detected by screening with LDCT is an overdiagnosis (PS), defined as the excess lung cancers detected by LDCT divided by all lung cancers detected by screening in the LDCT arm; and the number of cases that were considered overdiagnosis relative to the number of persons needed to screen to prevent 1 death from lung cancer.

Feb 2014

Intra- and Interscan Reproducibility Using Fourier Analysis of STimulated Echoes (FAST) for the Rapid and Robust Quantification of Left Ventricular Twist.

Reyhan M, Kim HJ, Brown MS, Ennis DB.

PURPOSE: To assess the intra- and interscan reproducibility of LV twist using FAST. Assessing the reproducibility of the measurement of new MRI biomarkers is an important part of validation. Fourier Analysis of STimulated Echoes (FAST) is a new MRI tissue tagging method that has recently been shown to compare favorably with conventional estimates of left ventricular (LV) twist from cardiac tagged images, but with significantly reduced user interaction time. MATERIALS AND METHODS: Healthy volunteers (N = 10) were scanned twice using FAST over 1 week. On day 1, two measurements of LV twist were collected for intrascan comparisons. Measurements for LV twist were again collected on day 8 for interscan assessment. LV short-axis tagged images were acquired on a 3 Tesla (T) scanner to ensure detectability of tags during early and mid-diastole. Peak LV twist is reported as mean ± SD. Reproducibility was assessed using the concordance correlation coefficient (CCC) and the repeatability coefficient (RC) (95% confidence interval [CI] range).

Feb 2014

Off-resonance Insensitive Complementary SPAtial Modulation of Magnetization (ORI-CSPAMM) for Quantification of Left Ventricular Twist.

Reyhan M, Natsuaki Y, Ennis DB.

PURPOSE: To evaluate Off Resonance Insensitive Complementary SPAtial Modulation of Magnetization (ORI-CSPAMM) and Fourier Analysis of STimulated echoes (FAST) for the quantification of left ventricular (LV) systolic and diastolic function and compare it with the previously validated FAST+SPAMM technique. MATERIALS AND METHODS: LV short-axis tagged images were acquired with ORI-CSPAMM and SPAMM in healthy volunteers (n = 13). The FAST method was used to automatically estimate LV systolic and diastolic twist parameters from rotation of the stimulated echo and stimulated anti-echo about the middle of k-space subsequent to ∼3 min of user interaction.

Feb 2014

Changes in Right Heart Haemodynamics and Echocardiographic Function in an Advanced Phenotype of Pulmonary Hypertension and Right Heart Dysfunction Associated with Pulmonary Fibrosis.

Saggar R, Khanna D, Vaidya A, Derhovanessian A, Maranian P, Duffy E, Belperio JA, Weigt SS, Dua S, Shapiro SS, Goldin JG, Abtin F, Lynch JP 3rd, Ross DJ, Forfia PR, Saggar R.

BACKGROUND: Pulmonary hypertension (PH)-targeted therapy in the setting of pulmonary fibrosis (PF) is controversial; the main clinical concern is worsening of systemic hypoxaemia. We sought to determine the effects of gentle initiation and chronic administration of parenteral treprostinil on right heart function in patients with PF associated with an advanced PH phenotype. METHODS: Open-label, prospective analysis of patients with PF-PH referred for lung transplantation (LT). Advanced PH was defined as mean pulmonary artery pressure (mPAP) ≥35 mm Hg. We compared haemodynamics, Doppler echocardiography (DE), oxygenation, dyspnoea and quality of life indices, and 6 min walk distance (6MWD) before and 12 weeks after parenteral treprostinil.

Feb 2014

Device Artifact Reduction for Magnetic Resonance Imaging of Patients with Implantable Cardioverter-defibrillators and Ventricular Tachycardia: Late Gadolinium Enhancement Correlation with Electroanatomic Mapping.

Stevens SM, Tung R, Rashid S, Gima J, Cote S, Pavez G, Khan S, Ennis DB, Finn JP, Boyle N, Shivkumar K, Hu P.

BACKGROUND: Late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) of ventricular scar has been shown to be accurate for detection and characterization of arrhythmia substrates. However, the majority of patients referred for ventricular tachycardia (VT) ablation have an implantable cardioverter-defibrillator (ICD), which obscures image integrity and the clinical utility of MRI. OBJECTIVE: The purpose of this study was to develop and validate a wideband LGE MRI technique for device artifact removal. METHODS: A novel wideband LGE MRI technique was developed to allow for improved scar evaluation on patients with ICDs. The wideband technique and the standard LGE MRI were tested on 18 patients with ICDs. VT ablation was performed in 13 of 18 patients with either endocardial and/or epicardial approach and the correlation between the scar identified on MRI and electroanatomic mapping (EAM) was analyzed.

Feb 2014

Target Lobe Volume Reduction and COPD Outcome Measures After Endobronchial Valve Therapy.

Valipour A, Herth FJ, Burghuber OC, Criner G, Vergnon JM, Goldin J, Sciurba F, Ernst A; VENT study group.

Endobronchial valve (EBV) therapy may be associated with improvements in chronic obstructive pulmonary disease-related outcomes and may therefore be linked to improvements in the body mass index, airflow obstruction, dyspnoea, exercise capacity (BODE) index. Data from 416 patients with advanced emphysema and hyperinflation across Europe and USA, who were randomised to EBV (n=284) or conservative therapy (n=132) were analysed. Quantitative image analysis was used to compare the volume of the targeted lobe at baseline and at 6 months to determine target lobe volume reduction (TLVR). 44% of patients receiving EBV therapy (versus 24.7% of controls) had clinically significant improvements in the BODE index (p<0.001). BODE index was significantly reduced by mean±sd 1.4±1.8, 0.2±1.3 and 0.1±1.3 points in patients with TLVR >50%, 20%-50% and <20%, respectively (intergroup differences p<0.001), but increased by 0.3±1.2 points in controls. Changes in BODE were predicted by baseline BODE and correlated significantly with lobar exclusion and lung volumes at 6 months. A greater proportion of patients in the treatment group than in the control group achieved a clinically meaningful improvement in BODE index; however, the likelihood of benefit was less than half in both groups. Patients in whom TLVR was obtained had greater improvements in clinical outcomes.

Feb 2014

Nonlinear Distortion Correction of Diffusion MR Images Improves Quantitative DTI Measurements in Glioblastoma.

Woodworth DC, Pope WB, Liau LM, Kim HJ, Lai A, Nghiemphu PL, Cloughesy TF, Ellingson BM.

The purpose of this study was to use a retrospective nonlinear distortion correction technique and evaluate the changes in DTI metrics in areas of interest in and around GBM tumors. A total of 24 histologically confirmed GBM patients with pre-operative 20-direction DTI scans were examined. Variability in apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in normal tissue before and after distortion correction were examined. Changes in mean, median and variance of ADC and FA in contrast enhancing and T2/FLAIR ROIs were also examined with and without distortion correction. Results suggest the intra-subject SDs of ADC and FA decreased in normal tissue after the application of distortion correction (P < 0.0001). FA mean and median values decreased after distortion correction in both T1+C and T2 ROIs (P < 0.017), while ADC mean and median values did not significantly change except for the median ADC in T1+C ROIs (P = 0.0054). The intra-subject SD of ADC and FA values in tumor ROIs changed significantly with distortion correction, and Bland-Altman analysis indicated that the bias and the SD of the bias of these intra-subject SDs were larger than those of the mean and median terms. Additionally, the means of the two curves of a double Gaussian fit to the histogram of ADC values from T1+C ROIs, ADCL (mean of lower Gaussian) as well as ADCH (mean of the higher Gaussian) were found to change significantly with distortion correction (P = 0.0045 for ADCL and P = 0.0370 for ADCH). Nonlinear distortion correction better aligns neuro-anatomical structures between DTI and anatomical scans, and significantly alters the measurement of values within tumor ROIs for GBM patients.

Feb 2014

Short-interval Estimation of Proliferation Rate Using Serial Diffusion MRI Predicts Progression-free Survival in Newly Diagnosed Glioblastoma Treated with Radiochemotherapy.

Zaw TM, Pope WB, Cloughesy TF, Lai A, Nghiemphu PL, Ellingson BM.

Cell invasion, motility, and proliferation level estimate (CIMPLE) mapping is a new imaging technique that provides parametric maps of microscopic invasion and proliferation rate estimates using serial diffusion MRI data. However, a few practical constraints have limited the use of CIMPLE maps as a tool for estimating these dynamic parameters, particularly during short-interval follow-up times. The purpose of the current study was to develop an approximation for the CIMPLE map solution for short-interval scanning involving the assumption that net intervoxel tumor invasion does not occur within sufficiently short time frames. Proliferation rate maps created using the "no invasion" approximation were found to be increasingly similar to maps created from full solution during increasingly longer follow-up intervals (3D cross correlation, R (2) = 0.5298, P = 0.0001). Results also indicate proliferation rate maps from the "no invasion" approximation had significantly higher sensitivity (82 vs. 64 %) and specificity (90 vs. 80 %) for predicting 6 month progression free survival and was a better predictor of time to progression during standard radiochemotherapy compared to the full CIMPLE solution (log-rank; no invasion estimation, P = 0.0134; full solution, P = 0.0555). Together, results suggest the "no invasion" approximation allows for quick estimation of proliferation rate using diffusion MRI data obtained from multiple scans obtained daily or biweekly for use in quantifying early treatment response.

Jan 2014

Pancreatic Ductal Adenocarcinoma Radiology Reporting Template: Consensus Statement of the Society of Abdominal Radiology and the American Pancreatic Association.

Al-Hawary MM, Francis IR, Chari ST, Fishman EK, Hough DM, Lu DS, Macari M, Megibow AJ, Miller FH, Mortele KJ, Merchant NB, Minter RM, Tamm EP, Sahani DV, Simeone DM.

Pancreatic ductal adenocarcinoma is an aggressive malignancy with a high mortality rate. Proper determination of the extent of disease on imaging studies at the time of staging is one of the most important steps in optimal patient management. Given the variability in expertise and definition of disease extent among different practitioners as well as frequent lack of complete reporting of pertinent imaging findings at radiologic examinations, adoption of a standardized template for radiology reporting, using universally accepted and agreed on terminology for solid pancreatic neoplasms, is needed. A consensus statement describing a standardized reporting template authored by a multi-institutional group of experts in pancreatic ductal adenocarcinoma that included radiologists, gastroenterologists, and hepatopancreatobiliary surgeons was developed under the joint sponsorship of the Society of Abdominal Radiologists and the American Pancreatic Association. Adoption of this standardized imaging reporting template should improve the decision-making process for the management of patients with pancreatic ductal adenocarcinoma by providing a complete, pertinent, and accurate reporting of disease staging to optimize treatment recommendations that can be offered to the patient. Standardization can also help to facilitate research and clinical trial design by using appropriate and consistent staging by means of resectability status, thus allowing for comparison of results among different institutions.

Jan 2014

Pancreatic Ductal Adenocarcinoma Radiology Reporting Template: Consensus Statement of the Society of Abdominal Radiology and the American Pancreatic Association.

Al-Hawary MM, Francis IR, Chari ST, Fishman EK, Hough DM, Lu DS, Macari M, Megibow AJ, Miller FH, Mortele KJ, Merchant NB, Minter RM, Tamm EP, Sahani DV, Simeone DM.

Pancreatic ductal adenocarcinoma is an aggressive malignancy with a high mortality rate. Proper determination of the extent of disease on imaging studies at the time of staging is one of the most important steps in optimal patient management. Given the variability in expertise and definition of disease extent among different practitioners as well as frequent lack of complete reporting of pertinent imaging findings at radiologic examinations, adoption of a standardized template for radiology reporting, using universally accepted and agreed on terminology for solid pancreatic neoplasms, is needed. A consensus statement describing a standardized reporting template authored by a multi-institutional group of experts in pancreatic ductal adenocarcinoma that included radiologists, gastroenterologists, and hepatopancreatobiliary surgeons was developed under the joint sponsorship of the Society of Abdominal Radiologists and the American Pancreatic Association. Adoption of this standardized imaging reporting template should improve the decision-making process for the management of patients with pancreatic ductal adenocarcinoma by providing a complete, pertinent, and accurate reporting of disease staging to optimize treatment recommendations that can be offered to the patient. Standardization can also help to facilitate research and clinical trial design by using appropriate and consistent staging by means of resectability status, thus allowing for comparison of results among different institutions.

Jan 2014

Defining the Critical-sized Defect in a Rat Segmental Mandibulectomy Model.

Deconde AS, Lee MK, Sidell D, Aghaloo T, Lee M, Tetradis S, Low K, Elashoff D, Grogan T, Sepahdari AR, St John M.

IMPORTANCE: Advances in tissue engineering offer potential alternatives to current mandibular reconstructive techniques; however, before clinical translation of this technology, a relevant animal model must be used to validate possible interventions. OBJECTIVE: To establish the critical-sized segmental mandibular defect that does not heal spontaneously in the rat mandible. DESIGN AND SETTING: Prospective study of mandibular defect healing in 29 Sprague-Dawley rats in an animal laboratory. INTERVENTIONS: The rats underwent creation of 1 of 4 segmental mandibular defects measuring 0, 1, 3, and 5 mm. All mandibular wounds were internally fixated with 1-mm microplates and screws and allowed to heal for 12 weeks, after which the animals were killed humanely. MAIN OUTCOMES AND MEASURES: Analysis with micro-computed tomography of bony union and formation graded on semiquantitative scales.

Jan 2014

The Effects of Noise Over the Complete Space of Diffusion Tensor Shape.

Gahm JK, Kindlmann G, Ennis DB.

Diffusion tensor magnetic resonance imaging (DT-MRI) is a technique used to quantify the microstructural organization of biological tissues. Multiple images are necessary to reconstruct the tensor data and each acquisition is subject to complex thermal noise. As such, measures of tensor invariants, which characterize components of tensor shape, derived from the tensor data will be biased from their true values. Previous work has examined this bias, but over a narrow range of tensor shape. Herein, we define the mathematics for constructing a tensor from tensor invariants, which permits an intuitive and principled means for building tensors with a complete range of tensor shape and salient microstructural properties. Thereafter, we use this development to evaluate by simulation the effects of noise on characterizing tensor shape over the complete space of tensor shape for three encoding schemes with different SNR and gradient directions. We also define a new framework for determining the distribution of the true values of tensor invariants given their measures, which provides guidance about the confidence the observer should have in the measures. Finally, we present the statistics of tensor invariant estimates over the complete space of tensor shape to demonstrate how the noise sensitivity of tensor invariants varies across the space of tensor shape as well as how the imaging protocol impacts measures of tensor invariants.

Jan 2014

Successful Patient Recruitment in CT Imaging Clinical Trials: What Factors Influence Patient Participation?

Hollada J, Marfori W, Tognolini A, Speier W, Ristow L, Ruehm SG.

RATIONALE AND OBJECTIVES: Analyze factors that influence participation in research studies that use coronary computed tomography (CT) imaging. MATERIALS AND METHODS: A 12-point survey using a questionnaire was conducted on 80 subjects, of whom 40 agreed to participate in a cardiovascular CT imaging research study (enrolling subjects) and 40 declined participation (non-enrolling subjects). Potential factors that motivated the acceptance or refusal of enrollment were evaluated using a 5-point Likert scale. The following aspects were addressed: (1) additional health information, (2) free imaging, (3) altruistic benefit to society, (4) monetary compensation, (5) radiation exposure, (6) role as an experimental subject, (7) possible loss of confidentiality, (8) contrast or investigational drug use, (9) premedication use, (10) blood draw or intravenous placement, (11) time commitment, and (12) personal medical opinion. Response distributions were obtained for each question and compared between enrolling and non-enrolling groups.

Jan 2014

Illuminating Radiogenomic Characteristics of Glioblastoma Multiforme through Integration of MR Imaging, Messenger RNA Expression, and DNA Copy Number Variation.

Jamshidi N, Diehn M, Bredel M, Kuo MD.

PURPOSE: To perform a multilevel radiogenomics study to elucidate the glioblastoma multiforme (GBM) magnetic resonance (MR) imaging radiogenomic signatures resulting from changes in messenger RNA (mRNA) expression and DNA copy number variation (CNV). MATERIALS AND METHODS: Radiogenomic analysis was performed at MR imaging in 23 patients with GBM in this retrospective institutional review board-approved HIPAA-compliant study. Six MR imaging features-contrast enhancement, necrosis, contrast-to-necrosis ratio, infiltrative versus edematous T2 abnormality, mass effect, and subventricular zone (SVZ) involvement-were independently evaluated and correlated with matched genomic profiles (global mRNA expression and DNA copy number profiles) in a significant manner that also accounted for multiple hypothesis testing by using gene set enrichment analysis (GSEA), resampling statistics, and analysis of variance to gain further insight into the radiogenomic signatures in patients with GBM.

Jan 2014

Isolated Choroid Plexus Granulomas: Initial Presentation of Neurosarcoidosis?

Kallen ME, Boon-Unge K, Yong WH, Pope WB, Frazee JG, Vinters HV.

We present an unusual case of an isolated granulomatous mass of the right lateral ventricle involving the choroid plexus, in an otherwise healthy patient with minimal significant past medical history.

Jan 2014

A Panel of Biomarkers is Associated with Increased Risk of the Presence and Progression of Atherosclerosis in Women with Systemic Lupus Erythematosus.

McMahon M, Skaggs BJ, Grossman JM, Sahakian L, Fitzgerald J, Wong WK, Lourenco EV, Ragavendra N, Charles-Schoeman C, Gorn A, Karpouzas GA, Taylor MB, Watson KE, Weisman MH, Wallace DJ, Hahn BH.

OBJECTIVE: An increased frequency of atherosclerosis (ATH) in systemic lupus erythematosus (SLE) is well-documented but not fully explained by the presence of traditional cardiac risk factors. Several nontraditional biomarkers, including proinflammatory high-density lipoprotein (piHDL) and leptin, have been individually associated with subclinical ATH in SLE. The aim of this study was to examine whether these and other biomarkers can be combined into a risk profile, the Predictors of Risk for Elevated Flares, Damage Progression, and Increased Cardiovascular Disease in Patients with SLE (PREDICTS), that could be used to better predict future progression of ATH. METHODS: In total, 210 patients with SLE and 100 age-matched healthy control subjects (all women) participated in this prospective cohort study. The longitudinal presence of carotid plaque and intima-media thickness (IMT) were measured at baseline and followup (mean ± SD 29.6 ± 9.7 months).

Jan 2014

Improved Late Gadolinium Enhancement MR Imaging for Patients with Implanted Cardiac Devices.

Rashid S, Rapacchi S, Vaseghi M, Tung R, Shivkumar K, Finn JP, Hu P.

PURPOSE: To propose and test a modified wideband late gadolinium enhancement (LGE) magnetic resonance (MR) imaging technique to overcome hyperintensity image artifacts caused by implanted cardiac devices. MATERIALS AND METHODS: Written informed consent was obtained from all participants, and the HIPAA-compliant study protocol was approved by the institutional review board. Studies in phantoms and in a healthy volunteer were performed to test the hypothesis that the hyperintensity artifacts that are typically observed on LGE images in patients with implanted cardiac devices are caused by insufficient inversion of the affected myocardial signal. The conventional LGE MR imaging pulse sequence was modified by replacing the nonselective inversion pulse with a wideband inversion pulse. The modified LGE sequence, along with the conventional LGE sequence, was evaluated in 12 patients with implantable cardioverter defibrillators (ICDs) who were referred for cardiac MR imaging.

Jan 2014

Evaluation of Alpha-Fetoprotein in Detecting Hepatocellular Carcinoma Recurrence After Radiofrequency Ablation.

Siripongsakun S, Wei SH, Lin S, Chen J, Raman SS, Sayre J, Tong MJ, Lu DS.

BACKGROUND AND AIM: The performance of alpha-fetoprotein (AFP) in the detection of hepatocellular carcinoma (HCC) recurrence after radiofrequency ablation was analyzed. METHODS: One hundred and forty-six solitary HCC lesions treated by radiofrequency ablation were evaluated. Using the AFP cutoff level at ≥ 20 ng/mL, tumors were categorized into AFP or non-AFP-producing HCC. Factors associated with true and false interpretations for cancer recurrence including analysis of elevated alanine aminotransferase (ALT) were evaluated. The performance of AFP using different cutoff levels adjusted for abnormal ALT was compared.

Jan 2014

Translabial Ultrasonography for Evaluation of Synthetic Mesh in the Vagina.

Staack A, Vitale J, Ragavendra N, Rodríguez LV.

OBJECTIVE: To compare the clinical and surgical findings using translabial ultrasonography (US) in the evaluation of symptoms after transvaginal synthetic mesh placement. METHODS: From 2009 through 2010, a retrospective observational study was conducted to evaluate patients presenting with complaints after transvaginal mesh implantation for the treatment of stress urinary incontinence or pelvic organ prolapse repair. The clinical and translabial US findings were compared with the intraoperative findings, with a focus on mesh location, erosion, and extrusion.

Jan 2014

Multidimensional MR Spectroscopic Imaging of Prostate Cancer in vivo.

Thomas MA, Nagarajan R, Huda A, Margolis D, Sarma MK, Sheng K, Reiter RE, Raman SS.

Prostate cancer (PCa) is the second most common type of cancer among men in the United States. A major limitation in the management of PCa is an inability to distinguish, early on, cancers that will progress and become life threatening. One-dimensional (1D) proton ((1) H) MRS of the prostate provides metabolic information such as levels of choline (Ch), creatine (Cr), citrate (Cit), and spermine (Spm) that can be used to detect and diagnose PCa. Ex vivo high-resolution magic angle spinning (HR-MAS) of PCa specimens has revealed detection of more metabolites such as myo-inositol (mI), glutamate (Glu), and glutamine (Gln). Due to the J-modulation and signal overlap, it is difficult to quantitate Spm and other resonances in the prostate clearly by single- and multivoxel-based 1D MR spectroscopy. This limitation can be minimized by adding at least one more spectral dimension by which resonances can be spread apart, thereby increasing the spectral dispersion. However, recording of multivoxel-based two-dimensional (2D) MRS such as J-resolved spectroscopy (JPRESS) and correlated spectroscopy (L-COSY) combined with 2D or three-dimensional (3D) magnetic resonance spectroscopic imaging (MRSI) using conventional phase-encoding can be prohibitively long to be included in a clinical protocol. To reduce the long acquisition time required for spatial encoding, the echo-planar spectroscopic imaging (EPSI) technique has been combined with correlated spectroscopy to give four-dimensional (4D) echo-planar correlated spectroscopic imaging (EP-COSI) as well as J-resolved spectroscopic imaging (EP-JRESI) and the multi-echo (ME) variants. Further acceleration can be achieved using non-uniform undersampling (NUS) and reconstruction using compressed sensing (CS). Earlier versions of 2D MRS, theory of 2D MRS, spectral apodization filters, newer developments and the potential role of multidimensional MRS in PCa detection and management will be reviewed here.

Jan 2014

Regional and Voxel-Wise Comparisons of Blood Flow Measurements Between Dynamic Susceptibility Contrast Magnetic Resonance Imaging (DSC-MRI) and Arterial Spin Labeling (ASL) in Brain Tumors.

White CM, Pope WB, Zaw T, Qiao J, Naeini KM, Lai A, Nghiemphu PL, Wang JJ, Cloughesy TF, Ellingson BM.

The objective of the current study was to evaluate the regional and voxel-wise correlation between dynamic susceptibility contrast (DSC) and arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI) measurement of cerebral blood flow (CBF) in patients with brain tumors. Thirty patients with histologically verified brain tumors were evaluated in the current study. DSC-MRI was performed by first using a preload dose of gadolinium contrast, then collecting a dynamic image acquisition during a bolus of contrast, followed by posthoc contrast agent leakage correction. Pseudocontinuous ASL was collected using 30 pairs of tag and control acquisition using a 3-dimensional gradient-echo spin-echo (GRASE) acquisition. All images were registered to a high-resolution anatomical atlas. Average CBF measurements within regions of contrast-enhancement and T2 hyperintensity were evaluated between the two modalities. Additionally, voxel-wise correlation between CBF measurements obtained with DSC and ASL were assessed. Results demonstrated a positive linear correlation between DSC and ASL measurements of CBF when regional average values were compared; however, a statistically significant voxel-wise correlation was only observed in around 30-40% of patients. These results suggest DSC and ASL may provide regionally similar, but spatially different measurements of CBF.

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