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UCLA Radiology


Research Publications

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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