Research Publications

December 2013

Rueff LE, Raman SS.

Although many women undergo hysterectomy for treatment of uterine fibroids, there are more options than ever before for fibroid treatment. A combination of objective criteria, including clinical parameters, anatomic factors, fibroid characteristics, and patient desires influence the choice of optimal therapeutic modality for a woman with symptomatic uterine fibroids. Magnetic resonance imaging-guided high intensity focused ultrasound (MR-HIFU) is the only noninvasive treatment option for women with symptomatic uterine fibroids unresponsive to medical treatment. The procedure has been shown to be safe and effective. MR-HIFU couples the three-dimensional multiplanar anatomic imaging and thermal monitoring capability of MR imaging with the therapeutic thermal-based coagulative necrosis mechanism of HIFU to safely and effectively ablate limited volume classical fibroids. In the author's experience, a multidisciplinary fibroid clinic facilitates a unified approach between gynecologists, radiologists, and others to individualize the most appropriate fibroid treatment options for each woman. This article describes the MR-HIFU technique and outcomes, as well as patient selection and treatment assessment.

December 2013

Saver JL, Jovin TG, Smith WS, Albers GW, Baron JC, Boltze J, Broderick JP, Davis LA, Demchuk AM, DeSena S, Fiehler J, Gorelick PB, Hacke W, Holt B, Jahan R, Jing H, Khatri P, Kidwell CS, Lees KR, Lev MH, Liebeskind DS, Luby M, Lyden P, Megerian JT, Mocco J, Muir KW, Rowley HA, Ruedy RM, Savitz SI, Sipelis VJ, Shimp SK 3rd, Wechsler LR, Wintermark M, Wu O, Yavagal DR, Yoo AJ; STAIR VIII Consortium.

BACKGROUND AND PURPOSE: The goal of the Stroke Treatment Academic Industry Roundtable (STAIR) meetings is to advance the development of stroke therapies. At STAIR VIII, consensus recommendations were developed for clinical trial strategies to demonstrate the benefit of endovascular reperfusion therapies for acute ischemic stroke. SUMMARY OF REVIEW: Prospects for success with forthcoming endovascular trials are robust, because new neurothrombectomy devices have superior reperfusion efficacy compared with earlier-generation interventions. Specific recommendations are provided for trial designs in 3 populations: (1) patients undergoing intravenous fibrinolysis, (2) early patients ineligible for or having failed intravenous fibrinolysis, and (3) wake-up and other late-presenting patients. Among intravenous fibrinolysis-eligible patients, key principles are that CT or MRI confirmation of target arterial occlusions should precede randomization; endovascular intervention should be pursued with the greatest rapidity possible; and combined intravenous and neurothrombectomy therapy is more promising than neurothrombectomy alone. Among patients ineligible for or having failed intravenous fibrinolysis, scientific equipoise was affirmed and the need to randomize all eligible patients emphasized. Vessel imaging to confirm occlusion is mandatory, and infarct core and penumbral imaging is desirable in later time windows. Additional STAIR VIII recommendations include approaches to test multiple devices in a single trial, utility weighting of disability end points, and adaptive designs to delineate time and tissue injury thresholds at which benefits from intervention no longer accrue.

December 2013

Wells CJ, O'Donoghue C, Ojeda-Fournier H, Retallack HE, Esserman LJ.

Our understanding of the biology of breast cancer has dramatically expanded over the past decade, revealing that breast cancer is a heterogeneous group of diseases. This new knowledge can generate insights to improve screening performance and the management of ductal carcinoma in situ. In this article, the authors review the current state of the science of breast cancer and tools that can be used to improve screening and risk assessment. They describe several opportunities to improve clinical screening: (1) radiologists interpreting mammograms should aim to differentiate between the risk for invasive cancer and ductal carcinoma in situ to better assess the time frame for disease progression and the need for and optimal timing of biopsy; (2) imaging features associated with low risk, slow-growing cancer versus high risk, fast-growing cancer should be better defined and taught; and (3) as we learn more about assessing an individual's risk for developing breast cancer, we should incorporate these factors into a strategy for personalized screening to maximize benefit and minimize harm.

November 2013

Ahmed M, de Rosales RT, Douek M.

BACKGROUND: One-third of all breast cancers are present as clinically nonpalpable lesions. The current gold standard treatment is surgical excision by wire-guided localization. This technique has patient, technical, and scheduling drawbacks. Alternatives exist but depend on radioisotopes with their legislative and waste management issues. Magnetic nanoparticles (MNPs) have already been successfully used for sentinel lymph node biopsy in breast cancer. We therefore aimed to determine the feasibility of using iron oxide MNPs and a handheld magnetometer for the localization of nonpalpable breast cancers using a preclinical model. METHODS: We constructed phantom models to assess the relationship between the handheld magnetometer peak readings and the variation in volume of iron oxide MNPs and their depth of injection in a series of porcine and avian tissue models. We also radiolabeled the MNPs with (99m)Tc and alendronate to create the conjugate (99m)Tc-dipicolylamine-alendronate-MNP and used nano-single-photon emission computed tomography-computed tomography to perform imaging to demonstrate localization properties.

November 2013

Argula RG, Strange C, Ramakrishnan V, Goldin J.

BACKGROUND: Advanced heterogeneous emphysema with hyperinflation impacts exercise tolerance in COPD. Bronchoscopic lung volume reduction using Zephyr endobronchial valves (EBVs) has been shown to improve lung function in patients with heterogeneous emphysema. It is unclear whether the target lobe perfusion of patients receiving EBV therapy impacts exercise tolerance as measured by the 6-min walk test distance (6MWTD). METHODS: We performed a retrospective analysis on the treatment group of the Endobronchial Valve for Emphysema Palliation Trial (VENT) to evaluate the impact of perfusion, measured by 99mTc-MAA-perfusion scintigraphy, on the 6-month improvement in 6MWTD. A mixed-model analysis was performed for the treatment outcome, adjusting for other variables such as age, target lobe position, fissure integrity, BMI, sex, destruction score, and lobar exclusion.

November 2013

Bui AA, Hsu W, Arnold C, El-Saden S, Aberle DR, Taira RK.

Imaging has become a prevalent tool in the diagnosis and treatment of many diseases, providing a unique in vivo, multi-scale view of anatomic and physiologic processes. With the increased use of imaging and its progressive technical advances, the role of imaging informatics is now evolving--from one of managing images, to one of integrating the full scope of clinical information needed to contextualize and link observations across phenotypic and genotypic scales. Several challenges exist for imaging informatics, including the need for methods to transform clinical imaging studies and associated data into structured information that can be organized and analyzed. We examine some of these challenges in establishing imaging-based observational databases that can support the creation of comprehensive disease models. The development of these databases and ensuing models can aid in medical decision making and knowledge discovery and ultimately, transform the use of imaging to support individually-tailored patient care.

November 2013

Charles-Schoeman C, Lee YY, Shahbazian A, Gorn AH, Fitzgerald J, Ranganath VK, Taylor M, Ragavendra N, McMahon M, Elashoff D, Reddy ST.

OBJECTIVE: To investigate the relationship of genetic and biochemical determinants of paraoxonase 1 activity to carotid plaque as a surrogate marker of cardiovascular (CV) risk in patients with rheumatoid arthritis (RA). METHODS: The relationships between paraoxonase 1 activity, PON1 genotype (for the functional polymorphism at position 192), and carotid plaque presence were determined in 168 RA patients. After an overnight fast, blood was collected for lipoprotein analysis, and paraoxonase 1 activity was measured using paraoxon as the substrate. The PON1 Q192R genotype was determined for all patients. Lipoprotein cholesterol levels, traditional CV risk factors, medication use, and RA disease characteristics were assessed for all patients.

November 2013

Chien A, Viñuela F.

BACKGROUND: Intracranial aneurysm flow diverting stents are a new endovascular treatment option for wide neck and large/giant aneurysms. Since August 2011, our center has integrated flow diverting stents into aneurysm treatment management. To further understand the effects of flow diverting stents, we developed the intracranial stent flow mapping program, which allows detailed, case by case, examination and comparison of blood flow changes within an aneurysm before and after stent treatment. METHODS: The Intracranial Stent Flow Mapping program (IS FlowMap) utilizes algorithms detecting movement changes between consecutive images. Sequences of catheter angiograms capturing the movement of injected contrast were used to map flow patterns and examine aneurysmal flow before and after stent implantation.

November 2013

Elbuluk O, Abemayor E, Sepahdari AR.

A 74-year-old woman presented with persistent dysphagia, dysphonia, and throat gurgling. Prior intraoperative biopsies were negative, and outside imaging revealed supraglottic swelling. Magnetic resonance imaging (MRI) demonstrated a well-defined T1 and T2 hypointense, avidly enhancing hypopharyngeal mass. Deep intraoperative rebiopsies revealed a tumor with CD34+ tissue, diagnostic of a solitary fibrous tumor. A broad range of nonsquamous cell tumors should be considered when a submucosal laryngeal mass is encountered. MRI may be particularly helpful in guiding appropriate biopsy.

November 2013

Fujimoto M, Tateshima S, Ali L, Raychev R, Viñuela F.

We describe a case of a 15-year-old girl who developed a spontaneous intracranial arterial dissection with distal middle cerebral artery (MCA) occlusions. From the digital subtraction angiography provided, the dissection flap appeared to originate at the internal carotid artery terminus with extension into the right M1 segment and occluding the right anterior cerebral artery, A1 segment. CT perfusion study showed salvageable tissue in the posterior MCA territory, including the motor cortex. In order to avoid further injury to the dissection, clot retrieval systems were not a treatment option. We therefore performed selective thrombus aspiration with the Penumbra system for the occluded central and precentral arteries distal to the non-occlusive dissecting lesion. Sufficient recanalization was achieved and the patient made a marked recovery. Although mechanical thrombectomy with the use of retrieval intracranial stent systems has demonstrated satisfactory recanalization rates, the aspiration methodology remains useful for patients with an accompanying proximal vascular lesion.

November 2013

Felker ER, Lee-Felker SA, Alpern L, Lu D, Raman SS.

OBJECTIVE. The purpose of this study was to determine the efficacy of imaging-guided percutaneous radiofrequency ablation (RFA) for the treatment of Bosniak category III and IV cystic renal lesions. MATERIALS AND METHODS. Our database was searched to assemble a cohort of biopsy-proven malignant Bosniak category III and IV cystic renal lesions that were treated with imaging-guided percutaneous RFA from 2004 to 2012. The clinical history, imaging features, procedural complications, pathologic results, imaging follow-up, and clinical outcomes of each case were reviewed.

November 2013

Hsu W, Markey MK, Wang MD.

Biomedical informatics is the interdisciplinary field that studies and pursues the effective uses of biomedical data, information, and knowledge for scientific inquiry, problem solving, and decision making, motivated by efforts to improve human health.1 ,2 Not only do biomedical informaticians study and develop theories, methods, and processes for the generation, manipulation, and sharing of biomedical data, but they also investigate how to model and reason on these data in order to effect beneficial change in the healthcare enterprise. In addition, an important aspect associated with developments in this field is the consideration of social and behavioral sciences in the design and evaluation of technical solutions. As a subfield of biomedical informatics, biomedical imaging informatics (BMII) encompasses all of the aforementioned aspects from the perspective of imaging. BMII has emerged as one of the fastest growing research areas in recent years given the evolution of techniques in molecular imaging, anatomical imaging, and functional imaging and advancements in imaging biomarker generation. Developments have also been accelerated by efforts to realize precision medicine,3 which necessitates a multiscale understanding of diseases that integrate insights in areas such as radiology, pathology, and genetics. This focus issue highlights the growing impact of BMII, demonstrating the increasing breadth of imaging modalities (eg, optical, molecular, in addition to traditional diagnostic modalities) and the diversity of specialties that depend on imaging information (eg, dermatology, pathology, surgery).

November 2013

Ishihara H, Tateshima S, Jahan R, Gonzalez N, Duckwiler G, Viñuela F.

BACKGROUND: Dissecting aneurysms of the posterior inferior cerebellar artery (PICA) are rare, with optimal treatment strategies not well established according to the location of the aneurysm on the PICA. We present our single-center experience of endovascular treatment of ruptured dissecting aneurysms of the PICA. METHODS: Nine patients with ruptured dissecting aneurysms of the PICA were treated with endovascular embolization at our facility from August 1997 to December 2011. A retrospective chart review study was conducted to examine the efficacy of endovascular treatment and clinical outcome.

November 2013

McMillan K, McNitt-Gray M, Ruan D.

PURPOSE: The purpose of this study is to adapt an equivalent source model originally developed for conventional CT Monte Carlo dose quantification to the radiation oncology context and validate its application for evaluating concomitant dose incurred by a kilovoltage (kV) cone-beam CT (CBCT) system integrated into a linear accelerator. METHODS: In order to properly characterize beams from the integrated kV CBCT system, the authors have adapted a previously developed equivalent source model consisting of an equivalent spectrum module that takes into account intrinsic filtration and an equivalent filter module characterizing the added bowtie filtration. An equivalent spectrum was generated for an 80, 100, and 125 kVp beam with beam energy characterized by half-value layer measurements. An equivalent filter description was generated from bowtie profile measurements for both the full- and half-bowtie. Equivalent source models for each combination of equivalent spectrum and filter were incorporated into the Monte Carlo software package MCNPX. Monte Carlo simulations were then validated against in-phantom measurements for both the radiographic and CBCT mode of operation of the kV CBCT system. Radiographic and CBCT imaging dose was measured for a variety of protocols at various locations within a body (32 cm in diameter) and head (16 cm in diameter) CTDI phantom. The in-phantom radiographic and CBCT dose was simulated at all measurement locations and converted to absolute dose using normalization factors calculated from air scan measurements and corresponding simulations. The simulated results were compared with the physical measurements and their discrepancies were assessed quantitatively.

November 2013

Nael K, Meshksar A, Liebeskind DS, Coull BM, Krupinski EA, Villablanca JP.

BACKGROUND AND PURPOSE: This study compares the concordance between arterial spin labeling (ASL) and dynamic susceptibility contrast (DSC) for the identification of regional hypoperfusion and diffusion-perfusion mismatch tissue classification using a quantitative method. METHODS: The inclusion criteria for this retrospective study were as follows: patients with acute ischemic syndrome with symptom onset <24 hours and acquisition of both ASL and DSC MR perfusion. The volumes of infarction and hypoperfused lesions were calculated on ASL and DSC multi-parametric maps. Patients were classified into reperfused, matched, or mismatch groups using time to maximum >6 sec as the reference. In a subset of patients who were successfully recanalized, the identical analysis was performed and the infarction and hypoperfused lesion volumes were used for paired pre- and posttreatment comparisons.

November 2013

Shih YC, Ganz PA, Aberle D, Abernethy A, Bekelman J, Brawley O, Goodwin JS, Hu JC, Schrag D, Temel JS, Schnipper L.

The national cost of cancer care is projected to reach $173 billion by 2020, increasing from $125 billion in 2010. This steep upward cost trajectory has placed enormous an financial burden on patients, their families, and society as a whole and raised major concern about the ability of the health care system to provide and sustain high-quality cancer care. To better understand the cost drivers of cancer care and explore approaches that will mitigate the problem, the National Cancer Policy Forum of the Institute of Medicine held a workshop entitled "Delivering Affordable Cancer Care in the 21st Century" in October 2012. Workshop participants included bioethicists, health economists, primary care physicians, and medical, surgical, and radiation oncologists, from both academic and community settings. All speakers expressed a sense of urgency about the affordability of cancer care resulting from the future demographic trend as well as the high cost of emerging cancer therapies and rapid diffusion of new technologies in the absence to evidence indicating improved outcomes for patients. This article is our summary of presentations at the workshop that highlighted the overuse and underuse of screening, treatments, and technologies throughout the cancer care continuum in oncology practice in the United States.

November 2013

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

OBJECT: Little is known about how much protection a flow diversion stent provides to a non-thrombosed aneurysm without the adjunctive use of coils. METHODS: A three-dimensional anatomically realistic computation aneurysm model was created from the digital subtraction angiogram of a large internal carotid artery-ophthalmic artery aneurysm which could have been treated with either a neck bridging stent or a flow diversion stent. Three-dimensional computational models of the Neuroform EZ neck bridging stent and Pipeline embolization device were created based on measurements with a stereo-microscope. Each stent was placed in the computational aneurysm model and intra-aneurysmal flow structures were compared before and after placement of the stents. Computational fluid dynamics were performed by numerically solving the continuity and Navier-Stokes momentum equations for a steady blood flow based on the finite volume method. Blood was assumed as an incompressible Newtonian fluid. Vessel walls were assumed to be rigid, and no-slip boundary conditions were applied at the lumens. To estimate the change in the intra-aneurysmal pressures we assumed that, at the inlets, the intra-arterial pressure at peak systole was 120 mm Hg both before and after stent placement

October 2013

Connolly M, Bilgin-Freiert A, Ellingson B, Dusick JR, Liebeskind D, Saver J, Gonzalez NR.

OBJECTIVES: Remote ischemic preconditioning (RIPC) is a powerful endogenous mechanism whereby a brief period of ischemia is capable of protecting remote tissues from subsequent ischemic insult. While this phenomenon has been extensively studied in the heart and brain in animal models, little work has been done to explore the effects of RIPC in human patients with acute cerebral ischemia. This study investigates whether chronic peripheral hypoperfusion, in the form of pre-existing arterial peripheral vascular disease (PVD) that has not been surgically treated, is capable of inducing neuroprotective effects for acute ischemic stroke. METHODS: Individuals with PVD who had not undergone prior surgical treatment were identified from a registry of stroke patients. A control group within the same database was identified by matching patient's demographics and risk factors. The two groups were compared in terms of outcome by NIH Stroke Scale (NIHSS), modified Rankin scale (mRS), mortality, and volume of infarcted tissue at presentation and at discharge. RESULTS: The matching algorithm identified 26 pairs of PVD-control patients (9 pairs were female and 17 pairs were male). Age range was 20-93 years (mean 73). The PVD group was found to have significantly lower NIHSS scores at admission (NIHSS≤4: PVD 47.1%, control 4.35%, p<0.003), significantly more favorable outcomes at discharge (mRS≤2: PVD 30.8%, control 3.84%, p<0.012), and a significantly lower mortality rate (PVD 26.9%, control 57.7%, p=0.024). Mean acute stroke volume at admission and at discharge were significantly lower for the PVD group (admission: PVD 39.6mL, control 148.3mL, p<0.005 and discharge: PVD 111.7mL, control 275mL, p<0.001).

October 2013

Liu CY, Liu YC, Wu C, Armstrong A, Volpe GJ, van der Geest RJ, Liu Y, Hundley WG, Gomes AS, Liu S, Nacif M, Bluemke DA, Lima JA.

OBJECTIVES: This study sought to determine the relationship of cardiovascular magnetic resonance (CMR) measures of tissue composition to age in the Multi-Ethnic Study of Atherosclerosis (MESA). BACKGROUND: Animal and human studies have demonstrated increased collagen deposition in senescent hearts. New CMR indices of tissue composition by using T1 mapping are sensitive to the presence of myocardial fibrosis. METHODS: A total of 1,231 study participants (51% women; age range 54 to 93 years) of the MESA cohort were evaluated with T1 mapping by using 1.5-T CMR scanners. None of the participants had focal scar on delayed enhancement CMR. Single-slice T1 mapping was performed at the midventricular level before and at 12- and 25-min delay after administration of gadolinium contrast by using a modified Look-Locker inversion recovery sequence. The partition coefficient was determined by the slope of the linear relationship of (1/T1myo vs. 1/T1blood). The extracellular volume fraction (ECV) was derived accounting for the hematocrit level. Multivariable regression analyses were performed, adjusting for traditional risk factors and left ventricular structure.

October 2013

Moore CM, Kasivisvanathan V, Eggener S, Emberton M, Fütterer JJ, Gill IS, Grubb Iii RL, Hadaschik B, Klotz L, Margolis DJ, Marks LS, Melamed J, Oto A, Palmer SL, Pinto P, Puech P, Punwani S, Rosenkrantz AB, Schoots IG, Simon R, Taneja SS, Turkbey B, Ukimura O, van der Meulen J, Villers A, Watanabe Y; START Consortium.

BACKGROUND: A systematic literature review of magnetic resonance imaging (MRI)-targeted prostate biopsy demonstrates poor adherence to the Standards for the Reporting of Diagnostic Accuracy (STARD) recommendations for the full and transparent reporting of diagnostic studies. OBJECTIVE: To define and recommend Standards of Reporting for MRI-targeted Biopsy Studies (START). DESIGN, SETTING, AND PARTICIPANTS: Each member of a panel of 23 experts in urology, radiology, histopathology, and methodology used the RAND/UCLA appropriateness methodology to score a 258-statement premeeting questionnaire. The collated responses were presented at a face-to-face meeting, and each statement was rescored after group discussion. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Measures of agreement and consensus were calculated for each statement. The most important statements, based on group median score, the degree of group consensus, and the content of the group discussion, were used to create a checklist of reporting criteria (the START checklist).

October 2013

Shino MY, Lynch JP 3rd, Saggar R, Abtin F, Belperio JA, Saggar R.

Pulmonary hypertension (PH) may complicate parenchymal lung disease, specifically interstitial lung diseases and chronic obstructive pulmonary disease, and uniformly increases the mortality risk. The epidemiology and degree of PH is variable and unique to the underlying lung disease. The clinician should exercise a high index of suspicion for PH complicating parenchymal lung disease especially given the nonspecific symptomatology and the limitations of echocardiography in this patient population. In general, PH-specific therapies in this setting have been poorly studied, with concern for increased shunting and/or ventilation/perfusion (V/Q) mismatch and resultant hypoxemia. A better understanding of the mechanisms underlying PH related to parenchymal lung disease may lead to novel pharmacological targets to prevent or treat this serious complication.

October 2013

Smith BM, Prince MR, Hoffman EA, Bluemke DA, Liu CY, Rabinowitz D, Hueper K, Parikh MA, Gomes AS, Michos ED, Lima JA, Barr RG.

BACKGROUND: COPD and heart failure with preserved ejection fraction overlap clinically, and impaired left ventricular (LV) filling is commonly reported in COPD. The mechanism underlying these observations is uncertain, but may include upstream pulmonary dysfunction causing low LV preload or intrinsic LV dysfunction causing high LV preload. The objective of this study is to determine if COPD and emphysema are associated with reduced pulmonary vein dimensions suggestive of low LV preload. METHODS: The population-based Multi-Ethnic Study of Atherosclerosis (MESA) COPD Study recruited smokers aged 50 to 79 years who were free of clinical cardiovascular disease. COPD was defined by spirometry. Percent emphysema was defined as regions < -910 Hounsfield units on full-lung CT scan. Ostial pulmonary vein cross-sectional area was measured by contrast-enhanced cardiac magnetic resonance and expressed as the sum of all pulmonary vein areas. Linear regression was used to adjust for age, sex, race/ethnicity, body size, and smoking.

October 2013

Villablanca JP, Duckwiler GR, Jahan R, Tateshima S, Martin NA, Frazee J, Gonzalez NR, Sayre J, Viñuela FV.

PURPOSE: To characterize the relationship between aneurysm size and epidemiologic risk factors with growth and rupture by using computed tomographic (CT) angiography. Materials and METHODS: In this HIPAA-compliant, institutional review board approved study, patients with known asymptomatic unruptured intracerebral aneurysms were followed up longitudinally with CT angiographic examinations. Growth was defined as an increase in one or more dimensions above the measurement error, and at least 5% volume by using the ABC/2 method. Associations of epidemiologic factors with aneurysm growth and rupture were analyzed by using logistic regression analysis. Intra- and interobserver agreement coefficients for dimension, volume, and growth were evaluated by using the Pearson correlation coefficient and difference of means with 95% confidence intervals, the agreement statistic, and the McNemar χ(2).

October 2013

Zhan L, Jahanshad N, Ennis DB, Jin Y, Bernstein MA, Borowski BJ, Jack CR Jr, Toga AW, Leow AD, Thompson PM.

Diffusion weighted magnetic resonance imaging (DW-MRI) are now widely used to assess brain integrity in clinical populations. The growing interest in mapping brain connectivity has made it vital to consider what scanning parameters affect the accuracy, stability, and signal-to-noise of diffusion measures. Trade-offs between scan parameters can only be optimized if their effects on various commonly-derived measures are better understood. To explore angular versus spatial resolution trade-offs in standard tensor-derived measures, and in measures that use the full angular information in diffusion signal, we scanned eight subjects twice, 2 weeks apart, using three protocols that took the same amount of time (7 min). Scans with 3.0, 2.7, 2.5 mm isotropic voxels were collected using 48, 41, and 37 diffusion-sensitized gradients to equalize scan times. A specially designed DTI phantom was also scanned with the same protocols, and different b-values. We assessed how several diffusion measures including fractional anisotropy (FA), mean diffusivity (MD), and the full 3D orientation distribution function (ODF) depended on the spatial/angular resolution and the SNR. We also created maps of stability over time in the FA, MD, ODF, skeleton FA of 14 TBSS-derived ROIs, and an information uncertainty index derived from the tensor distribution function, which models the signal using a continuous mixture of tensors. In scans of the same duration, higher angular resolution and larger voxels boosted SNR and improved stability over time. The increased partial voluming in large voxels also led to bias in estimating FA, but this was partially addressed by using "beyond-tensor" models of diffusion.

September 2013

Aberle DR, DeMello S, Berg CD, Black WC, Brewer B, Church TR, Clingan KL, Duan F, Fagerstrom RM, Gareen IF, Gatsonis CA, Gierada DS, Jain A, Jones GC, Mahon I, Marcus PM, Rathmell JM, Sicks J; National Lung Screening Trial Research Team.

BACKGROUND: The National Lung Screening Trial was conducted to determine whether three annual screenings (rounds T0, T1, and T2) with low-dose helical computed tomography (CT), as compared with chest radiography, could reduce mortality from lung cancer. We present detailed findings from the first two incidence screenings (rounds T1 and T2). METHODS: We evaluated the rate of adherence of the participants to the screening protocol, the results of screening and downstream diagnostic tests, features of the lung-cancer cases, and first-line treatments, and we estimated the performance characteristics of both screening methods.

September 2013

Dyer DS, Mohammed TL, Kirsch J, Amorosa JK, Brown K, Chung JH, Ginsburg ME, Heitkamp DE, Kanne JP, Kazerooni EA, Ketai LH, Anthony Parker J, Ravenel JG, Saleh AG, Shah RD; Expert Panel on Thoracic Imaging.

Dyspnea, described as breathlessness or shortness of breath, is usually caused by cardiopulmonary disease. The role of imaging in chronic dyspnea (>1 mo in duration) with suspected pulmonary origin is reviewed as suggested by the American College of Radiology Appropriateness Criteria Expert Panel on Thoracic Imaging. The American College of Radiology 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.

September 2013

Ellingson BM, Mayer E, Harris RJ, Ashe-McNally C, Naliboff BD, Labus JS, Tillisch K.

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by recurring abdominal pain associated with alterations in bowel habits. We hypothesized that patients with chronic visceral pain associated with IBS may have microstructural differences in the brain compared with healthy control subjects (HCs), indicative of long-term neural reorganization of chronic pain pathways and regions associated with sensory integration. In the current study we performed population-based voxel-wise diffusion tensor imaging (DTI) comparisons and probabilistic tractography in a large sample of phenotyped patients with IBS (n=33) and in HCs (n=93). Patients had lower fractional anisotropy (FA) in thalamic regions, the basal ganglia (BG) and sensory/motor association/integration regions as well as higher FA in frontal lobe regions and the corpus callosum. In addition, patients had reduced mean diffusivity (MD) within the globus pallidus (GP) and higher MD in the thalamus, internal capsule, and coronal radiata projecting to sensory/motor regions, suggestive of differential changes in axon/dendritic density in these regions. Sex differences in FA and MD were also observed in the patients but not in HCs. Probabilistic tractography in patients confirmed a higher degree of connectivity between the thalamus and prefrontal cortex, as well as between the medial dorsal thalamic nuclei and anterior cingulate cortex, and a lower degree of connectivity between the GP and thalamus. Together, these results support the hypothesis that patients with chronically recurring visceral pain from IBS have long-term microstructural changes within the brain, particularly in regions associated with integration of sensory information and corticothalamic modulation.

September 2013

Goldin JG.

There has been increasing interest in developing novel pulmonary biomarkers to assist in drug and device development in the setting of patients with chronic obstructive pulmonary disease and diffuse parenchymal lung disease. In this review we discuss which computed tomography (CT)-based biomarkers are currently being implemented and the challenges inherent in their development, validation, and implementation in multicenter trials. CT scans provide valuable information about lung structure and function but face challenges with respect to standardization across multiple sites and time points; in addition, the concern around radiation has to be considered. There is relatively little information about how any of these biomarkers relate to other clinical outcomes such as progression of disease, severity of disease, clinical subtypes, or response to therapy. Additional information is also needed about the variability in these measurements. In the future, CT biomarkers may be useful in predicting disease progression, in indicating disease instability, and in predicting response to current and novel therapies, many of which are now under development.

September 2013

Huo J, Okada K, van Rikxoort EM, Kim HJ, Alger JR, Pope WB, Goldin JG, Brown MS.

PURPOSE: Ensemble segmentation methods combine the segmentation results of individual methods into a final one, with the goal of achieving greater robustness and accuracy. The goal of this study was to develop an ensemble segmentation framework for glioblastoma multiforme tumors on single-channel T1w postcontrast magnetic resonance images. METHODS: Three base methods were evaluated in the framework: fuzzy connectedness, GrowCut, and voxel classification using support vector machine. A confidence map averaging (CMA) method was used as the ensemble rule.

September 2013

McLaughlin N, Raychev R, Duckwiler G, Martin NA.

The finding of dilated, elongated, and tortuous vessels on brain imaging should prompt clinicians to determine what vascular anomaly is present. Importantly, not all suspicious serpentine flow voids are manifestations of arteriovenous malformations or arteriovenous fistulas. Other types of intracranial vasculopathies should also be considered. The authors report a rare case of dilated, tortuous, and redundant left posterior communicating artery and left P2 segment of the posterior cerebral artery identified in a young healthy adult that remained stable over a 30-year period. Dynamic and 3D images were critical for determining the type of vascular anomaly and for guiding appropriate management. The authors propose that this case represents a pure arterial malformation and discuss its distinguishing features.

September 2013

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.

September 2013

Zhang D, Cagnon CH, Villablanca JP, McCollough CH, Cody DD, Zankl M, Demarco JJ, McNitt-Gray MF.

PURPOSE: CT neuroperfusion examinations are capable of delivering high radiation dose to the skin or lens of the eyes of a patient and can possibly cause deterministic radiation injury. The purpose of this study is to: (a) estimate peak skin dose and eye lens dose from CT neuroperfusion examinations based on several voxelized adult patient models of different head size and (b) investigate how well those doses can be approximated by some commonly used CT dose metrics or tools, such as CTDIvol, American Association of Physicists in Medicine (AAPM) Report No. 111 style peak dose measurements, and the ImPACT organ dose calculator spreadsheet. METHODS: Monte Carlo simulation methods were used to estimate peak skin and eye lens dose on voxelized patient models, including GSF's Irene, Frank, Donna, and Golem, on four scanners from the major manufacturers at the widest collimation under all available tube potentials. Doses were reported on a per 100 mAs basis. CTDIvol measurements for a 16 cm CTDI phantom, AAPM Report No. 111 style peak dose measurements, and ImPACT calculations were performed for available scanners at all tube potentials. These were then compared with results from Monte Carlo simulations.

August 2013

Choi EY, Rosen BD, Fernandes VR, Yan RT, Yoneyama K, Donekal S, Opdahl A, Almeida AL, Wu CO, Gomes AS, Bluemke DA, Lima JA.

AIMS: Left ventricular (LV) circumferential strain (Ecc) is a sensitive index of regional myocardial function. Currently, no studies have assessed its prognostic value in general population. We sought to investigate whether Ecc has a prognostic value for predicting incident heart failure (HF) and other major cardiovascular events in asymptomatic individuals without a history of previous cardiovascular diseases. METHODS AND RESULTS: We, prospectively, assessed incident HF and atherosclerotic events during a 5.5 ± 1.3-year period in 1768 asymptomatic individuals aged 45-84 (mean age 65 years; 47% female) who underwent tagged magnetic resonance imaging for strain determination. During the follow-up period, 39 (2.2%) participants experienced incident HF and 108 (6.1%) participants had atherosclerotic cardiovascular events. Average of peak Ecc of 12-LV segments (Ecc-global) and mid-slice (Ecc-mid) was -17.0 ± 2.4 and -17.5 ± 2.7%, respectively. Participants with average absolute Ecc-mid lower than -16.9% had a higher cumulative hazard of incident HF (log-rank test, P = 0.001). In cox regression analysis, Ecc-mid predicted incident HF independent of age, diabetes status, hypertension, interim myocardial infarction, LV mass index, and LV ejection fraction (hazard ratio 1.15 per 1%, 95% CI: 1.01-1.31, P = 0.03). This relationship remained significant after adjustment for LV-end-systolic wall stress into covariates. In addition, by adding Ecc-mid to risk factors, LV ejection fraction, and the LV mass index, both the global χ(2) value (76.6 vs. 82.4, P = 0.04) and category-less net-reclassification index (P = 0.01, SE = 0.18, z = 2.53) were augmented for predicting HF. Circumferential strain was also significantly related to the composite atherosclerotic cardiovascular events, but its relationship was attenuated after introducing the LV mass index.

August 2013

Finley DS, Margolis D, Raman SS, Ellingson BM, Natarajan S, Tan N, Huang J, Reiter RE.

OBJECTIVES: Robot-assisted radical prostatectomy (RARP) has now become the most common surgical treatment option for prostate cancer (CaP). Clinicopathologic data (i.e., biopsy, digital rectal exam, prostate specific antigen level) and patient-specific factors (e.g., age, erectile function, co-morbidities) are the primary sources of information that urologists use for counseling and treatment decision making. Magnetic resonance imaging (MRI) has evolved along a similar temporal arc to RARP, with increased utilization and precision over the past decade. MRI prior to RARP provides multifaceted adjunctive information, including enhancement of locoregional staging, delineation of spatial anatomic information, and identification of aberrant anatomy, all of which aid in patient treatment counseling and operative planning. This article is designed for urologic surgeons who perform RARP, with the aim of providing a review of prostate MRI imaging and highlighting findings which may specifically alter the operation. METHODS AND MATERIALS: A review of the literature was performed, focusing on the most recent publications.

August 2013

Lee MK, Sepahdari A, Cohen M.

OBJECTIVE: Ptosis of the submandibular glands is a well-recognized yet poorly quantified element of the aging face and neck. The goal of this study is to describe and quantify the rate and extent of age-related submandibular gland ptosis. A novel grading system is proposed to quantify the degree of descent of the submandibular gland in relation to the inferior border of the mandible. Implications for facial rejuvenation surgery are discussed.Study Design Retrospective review. METHODS: Consecutive computed tomography (CT) imaging studies performed at a university-affiliated hospital were selected for review. Using cross-referenced images in the coronal and axial planes, distance measurements were obtained from the bottom of the submandibular gland to the plane of the inferior border of the mandible. These data points were plotted against subject age for statistical analysis. The position of the submandibular gland was then categorized as grade I when distance below the mandible was < 20 mm, grade II for 20 to 25 mm, grade III for 25 to 30 mm, and grade IV for > 30 mm. Volumetric analysis was performed in a subset of subjects to assess for the possibility of age-related submandibular gland volume changes as a potential confounding factor in distance measurements.

August 2013

Massoud TF.

BACKGROUND: Transvenous retrograde nidus sclerotherapy under controlled hypotension (TRENSH) is a proposed novel concept for endovascular treatment of cerebral arteriovenous malformations (AVMs). OBJECTIVE: To assess the experimental hemodynamic feasibility of TRENSH in a pig AVM model. METHODS: We surgically constructed carotid-jugular fistula-type AVM models in 8 pigs. In 5 pigs (group 1) we hemodynamically assessed the AVM through the main arterial feeder (AF) and draining vein (DV) at systemic normotension (Systnorm). We then performed retrograde nidus angiography through the DV at progressively deeper levels of hemorrhagic systemic hypotension (Systhypo), and graded and correlated these angiograms with the degree of Systhypo. In another 3 pigs (group 2) we correlated the effects of temporary balloon occlusion of the main AF with the angiographic extent of retrograde nidus filling.

August 2013

Sung K, Daniel BL, Hargreaves BA.

PURPOSE: To quantify B1+ variation across the breasts and to evaluate the accuracy of precontrast T1 estimation with and without B1+ variation in breast MRI patients at 3 Tesla (T). MATERIALS AND METHODS: B1+ and variable flip angle (VFA) T1 mapping were included in our dynamic contrast-enhanced (DCE) breast imaging protocol to study a total of 25 patients on a 3.0T GE MR 750 system. We computed precontrast T1 relaxation in fat, which we assumed to be consistent across a cohort of breast imaging subjects, with and without compensation for B1+ variation. The mean and standard deviation of B1+ and T1 values were calculated for statistical data analysis.

August 2013

Yuki I, Kan I, Golshan A, Sohn J, Murayama Y, Vinters HV, Viñuela F.

SUMMARY: We report a novel swine model that allows direct visualization of cervical arteries undergoing mechanical thrombectomy. The model also facilitates evaluation of histologic changes observed in the arteries after treatment. Swine superficial cervical arteries, which are similar in size and branching pattern to the human middle cerebral artery, were surgically exposed, occluded with experimental thrombus, and subsequently treated with the Merci clot retriever device. Angiographic and histologic assessment were performed.

July 2013

Brown K, Gutierrez AJ, Mohammed TL, Kirsch J, Chung JH, Dyer DS, Ginsburg ME, Heitkamp DE, Kanne JP, Kazerooni EA, Ketai LH, Parker JA, Ravenel JG, Saleh AG, Shah RD, Steiner RM, Suh RD; Expert Panel on Thoracic Imaging.

Pulmonary hypertension (PH) may be idiopathic or related to a variety of diseases. The diagnosis, accurate assessment of etiology and severity, prognosis, treatment response, and follow-up of PH can be achieved using a diverse set of diagnostic examinations. In this review, the role of imaging in the evaluation of PH as suggested by the American College of Radiology Appropriateness Criteria Expert Panel on Thoracic Imaging has been discussed. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The development and review of the guidelines 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.

July 2013

Chien A, Liang F, Sayre J, Salamon N, Villablanca P, Viñuela F.

Object This study was performed to investigate the risk factors related to the growth of small, asymptomatic, unruptured aneurysms in patients with no history of subarachnoid hemorrhage (SAH). Methods Between January 2005 and December 2010, a total of 508 patients in whom unruptured intracranial aneurysms were diagnosed at the University of California, Los Angeles medical center did not receive treatment to prevent rupture. Of these, 235 patients with no history of SAH who had asymptomatic, small, unruptured aneurysms (< 7 mm) were monitored with 3D CT angiography images. Follow-up images of the lesions were used to measure aneurysm size changes. Patient medical history, family history of SAH, aneurysm size, and location were studied to find the risk factors associated with small aneurysm growth. Results A total of 319 small aneurysms were included, with follow-up durations of 29.2 ± 20.6 months. Forty-two aneurysms increased in size during the follow-up; 5 aneurysms grew to become ≥ 7 mm within 38.2 ± 18.3 months. A trend of higher growth rates was found in single aneurysms than in multiple aneurysms (p = 0.07). A history of stroke was the only factor associated with single aneurysm growth (p = 0.03). The number of aneurysms (p = 0.011), number of aneurysms located within the posterior circulation (p = 0.030), and patient history of transient ischemic attack (p = 0.044) were related to multiple aneurysm growth. Conclusions Multiple small aneurysms are more likely to grow, and multiple aneurysms located in the posterior circulation may require additional attention. Although single aneurysms have a lower risk of growth, a trend of higher growth rates in single aneurysms was found.

July 2013

Froehler MT, Tateshima S, Duckwiler G, Jahan R, Gonzalez N, Viñuela F, Liebeskind D, Saver JL, Villablanca JP; UCLA Stroke Investigators.

BACKGROUND: The success of mechanical clot retrieval for acute ischemic stroke may be influenced by the characteristics of the occlusive thrombus. The thrombus can be partly characterized by CT, as the hyperdense vessel sign (HVS) suggests erythrocyte-rich clot whereas fibrin-rich clot may be isodense. We hypothesized that the physical clot characteristics that determine CT density may also determine likelihood of retrieval with the Merci device. METHODS: We reviewed all acute stroke cases initially imaged with non-contrast CT before attempted Merci clot retrieval at a single center between 2004 and 2010. Each CT was blindly assessed for the presence or absence of the HVS, and post-retrieval angiograms were blindly assessed for reperfusion using the TICI scale.

July 2013

Fujimoto M, Shobayashi Y, Tateshima S, Vinters HV, Viñuela F.

OBJECTIVES: Endovascular treatment with the Wingspan Stent is frequently associated with in-stent restenosis at the curved portion, leading to late-phase stroke. To explore the cause of stroke complications after treatment with the Wingspan Stent, we simulated the biomechanical responses at a curved arterial segment using the finite element method. METHODS: A Wingspan stent was deployed at a slightly curved ascending pharyngeal artery (APA) in swine. Several stress distributions modeling solid mechanics were analyzed with structural deformation. Histopathological analysis of the selected APA was assessed at 28 days after stenting.

July 2013

Hauptman JS, Dadour A, Oh T, Baca CB, Vickrey BG, Vassar S, Sankar R, Salamon N, Vinters HV, Mathern GW.

BACKGROUND: It is unclear if socioeconomic factors like type of insurance influence time to referral and developmental outcomes for pediatric patients undergoing epilepsy surgery. OBJECTIVE:: This study determined whether private compared with state government insurance was associated with shorter intervals of seizure onset to surgery and better developmental quotients for pediatric patients undergoing epilepsy surgery. METHODS: A consecutive cohort (n = 420) of pediatric patients undergoing epilepsy surgery were retrospectively categorized into those with Medicaid (California Children's Services; n = 91) or private (Preferred Provider Organization, Health Maintenance Organization, Indemnity; n = 329) insurance. Intervals from seizure onset to referral and surgery and Vineland developmental assessments were compared by insurance type with the use of log-rank tests.

July 2013

Kruger R, Flynn MJ, Judy PF, Cagnon CH, Seibert JA.

OBJECTIVE: The National Lung Screening Trial (NLST) is a multicenter randomized controlled trial comparing low-dose helical CT with chest radiography in the screening of older current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004, when 53,454 participants had been randomized at 33 screening sites. The objective of this study was to determine the effective radiation dose associated with individual chest radiographic screening examinations. SUBJECTS AND METHODS: A total of 73,733 chest radiographic examinations were performed with 92 chest imaging systems. The entrance skin air kerma (ESAK) of participants' chest radiographic examinations was estimated and used in this analysis. The effective dose per ESAK for each examination was determined with a Monte Carlo-based program. The examination effective dose was calculated as the product of the examination ESAK and the Monte Carlo estimate of the ratio of effective dose per ESAK.

July 2013

Otto Baerlocher M, Nikolic B, Silberzweig JE, Kinney TB, Kuo MD, Rose SC.

The American Society of Anesthesiologists (ASA) produces the Standards for Basic Anesthetic Monitoring for appropriate patient monitoring during basic anesthesia (1). The standards document is periodically revised and updated, and includes recommendations for the use of moderate and deep sedation. As a number of nonanesthesiology specialists, including gastroenterologists, orthopedic surgeons, cardiologists, gynecologists, emergency room physicians, dentists, and, of course, interventional radiologists, use moderate sedation for procedures, most hospitals and clinics incorporate the ASA guidelines into sedation credentialing. Therefore, any significant change in the ASA standards for moderate and deep sedation will have a downstream impact on most interventional radiologists' practices.

July 2013

Patsalides A, Bulsara KR, Hsu DP, Abruzzo T, Narayanan S, Jayaraman MV, Duckwiler G, Klucznik RP, Kelly M, Hirsch JA, Heck D, Sunshine J, Frei D, Alexander MJ, Do HM, Meyers PM.

Since its inception, coil embolization of cerebral aneurysms was designed and approved by the US Food and Drug Administration for aneurysms considered to be high risk for microsurgical clip ligation, but it is now increasingly considered as the first line of treatment. The techniques for endovascular aneurysm treatment have evolved: new devices have been developed that allow treatment of aneurysms with anatomy previously unfavorable for endovascular occlusion, and indications for endovascular treatment have expanded. Nevertheless, intrasaccular coil embolization has become the mainstay of endovascular aneurysm treatment at the present time, and the medical literature demonstrates better outcomes with treatment by coiling than with clipping in specific patient groups.^1-3 In a recent scientific statement from the American Heart Association (AHA),⁴ either endovascular or microsurgical treatment of cerebral aneurysms amenable to treatment was indicated with AHA Class I level of recommendation for ruptured aneurysms and Class IIa for unruptured aneurysms. In both groups the evidence suggests that the benefit of treatment outweighs the risks. A multidisciplinary team experienced in vascular microneurosurgery, neurocritical care and neurointerventional surgery most appropriately applies best techniques to the management of intracranial aneurysms. The Neurovascular Coalition Writing Group has previously published recommendations for training and competence in cerebrovascular intervention with a joint statement.⁵

July 2013

Sepahdari AR, Yeh MW, Rodrigues D, Khan SN, Harari A.

OBJECTIVE: Multiphase multidetector contrast-enhanced parathyroid CT (4-dimensional computed tomography [4D-CT]) is an emerging tool for evaluating patients with primary hyperparathyroidism. Our goal was to describe the initial performance of 2 inexperienced readers in interpretation of 4D-CT. METHODS: Twenty-three subjects who received 4D-CT and successful surgical exploration were studied (14 initial and 9 repeat explorations; 15 single-gland disease and 8 multigland disease) A staff neuroradiologist prospectively interpreted all studies, and a neuroradiology fellow retrospectively interpreted all studies; their results were compared with the surgical findings for each side of the neck separately.

July 2013

Shi ZS, Loh Y, Gonzalez N, Tateshima S, Feng L, Jahan R, Duckwiler G, Viñuela F.

OBJECTIVES: Experience of flow control techniques during endovascular treatment of intracranial dural arteriovenous fistulas (DAVFs) using the Onyx liquid embolic system is reported, with an emphasis on high flow shunts. METHODS: Data were evaluated in patients with DAVFs treated endovascularly with Onyx. Adjunctive techniques with coils, acrylics and balloon assistance were utilized to reduce the rate of flow with transarterial and transvenous approaches.

July 2013

Turk A, Turner RD, Tateshima S, Fiorella D, Jang KS, Chaudry I, Kelly M.

INTRODUCTION: Treatment of wide-necked bifurcation aneurysms often poses procedural and long-term outcome challenges. The initial preclinical experience with the Pulsar Vascular Aneurysm Neck Reconstruction Device (PVANRD) in a canine bifurcation model is described. METHODS: Experimental bifurcation vein pouch aneurysms were surgically created in the carotid arteries of eight dogs. Endovascular coiling of the aneurysms with assistance of the PVANRD was performed in all cases with acute performance compared with Y-stenting.

June 2013

Akhtari M, Pope W, Mathern G, Moats R, Frew A, Mandelkern M.

PURPOSE: The development of nonradioactive and targeted magnetonanoparticles (MNP) capable of crossing the blood-brain barrier (BBB) and of concentrating in and enhancing the contrast of intracranial tumors on magnetic resonance imaging (MRI). PROCEDURE: Nonradioactive 2-deoxy-D-glucose (2DG) was covalently attached to magnetonanoparticles composed of iron oxide and dextran and prepared for intravenous (tail) injection in the naïve rats and mouse models of glioma. MR images were acquired at 3 and 7 T.

June 2013

Albores J, Seki A, Fishbein MC, Abtin F, Lynch JP 3rd, Wang T, Weigt SS.

We present a case of pulmonary alveolar proteinosis (PAP) initially diagnosed 28 months after left single-lung transplantation for idiopathic pulmonary fibrosis. The diagnosis was based upon the presence of periodic acid-Schiff (PAS)-positive and surfactant immunostain-positive acellular lipoproteinaceous material within alveoli seen on transbronchial biopsy as well as in bronchoalveolar lavage fluid. The patient eventually also displayed a characteristic "crazy paving" pattern on radiographic imaging. Granulocyte macrophage-colony stimulating factor antibodies were negative, consistent with secondary PAP. PAP is a rare interstitial lung disease with only a few reported cases occurring after lung transplantation. The etiology is thought to be related to a defect in macrophage function caused by immunosuppression. Reduced immunosuppression has been associated with stabilization, but not reversal, of the condition in the case reported here. PAP is an exceptionally rare cause of dyspnea and radiographic infiltrates after lung transplantation and may be related to toxicity of immune-suppressive medications.

June 2013

Khan SN, Rapacchi S, Levi DS, Finn JP.

BACKGROUND: To predict the type and extent of CMR artifacts caused by commonly used pediatric trans-catheter devices at 1.5 T and 3 T as an aid to clinical planning and patient screening. METHODS: Eleven commonly used interventional, catheter-based devices including stents, septal occluders, vascular plugs and embolization coils made from either stainless steel or nitinol were evaluated ex-vivo at both 1.5T and 3T. Pulse sequences and protocols commonly used for cardiovascular magnetic resonance (CMR) were evaluated, including 3D high-resolution MR angiography (MRA), time-resolved MRA, 2D balanced-SSFP cine and 2D phase-contrast gradient echo imaging (GRE). We defined the signal void amplification factor (F) as the ratio of signal void dimension to true device dimension. F1 and F2 were measured in the long axis and short axes respectively of the device. We defined F3 as the maximum extent of the off-resonance dark band artifact on SSFP measured in the B0direction. The effects of field strength, sequence type, orientation, flip angle and phase encode direction were tested. Clinical CMR images in 3 patients with various indwelling devices were reviewed for correlation with the in-vitro findings.

June 2013

Lee RJ, Saylor PJ, Dror Michaelson M, Michael Rothenberg S, Smas ME, Miyamoto DT, Gurski CA, Xie W, Maheswaran S, Haber DA, Goldin JG, Smith MR.

BACKGROUND: Cabozantinib is an oral MET/VEGFR2 inhibitor. A recent phase II study of cabozantinib (100 mg daily) showed improved bone scans in subjects with metastatic castration-resistant prostate cancer (mCRPC), but adverse events (AE) caused frequent dose reductions. This study was designed to determine the efficacy and tolerability of cabozantinib at lower starting doses. EXPERIMENTAL DESIGN: An adaptive design was used to determine the lowest active daily dose among 60, 40, and 20 mg. The primary endpoint was week 6 bone scan response, defined as ≥30% decrease in bone scan lesion area. The secondary endpoint was change in circulating tumor cells (CTC).

June 2013

Lubicz B, Mine B, Collignon L, Brisbois D, Duckwiler G, Strother C.

BACKGROUND AND PURPOSE: The WEB is an intrasaccular flow disrupter dedicated to EVT of IA. We report our initial experience in a series of patients treated with this device. MATERIALS AND METHODS: This prospective study was approved by the authors' ethical committees. Nineteen patients with 20 unruptured wide-neck bifurcation IAs were treated by WEB placement. Technical issues, immediate posttreatment angiographic findings, and clinical and imaging follow-up at 3, 6, and 12 months were assessed.

June 2013

Tamplen M, Blackwell K, Jahan R, Nabili V.

OBJECTIVES: To evaluate the efficacy of highly selective catheter-directed thrombolysis (CDT) and angioplasty for salvage of compromised free flaps that were performed for treatment of mandibular osteoradionecrosis (ORN). PATIENTS: Two patients with ORN who underwent highly selective CDT to salvage threatened free flaps are reported. One patient experienced arterial thrombosis on postoperative day 8 and underwent arterial CDT and angioplasty. A second patient underwent central venous CDT for a subclavian vein thrombosis that was diagnosed during the immediate postoperative period. INTERVENTIONS: Highly selective CDT and angioplasty for salvage of compromised free flaps. MAIN OUTCOMES MEASURED: Flap survival, patient survival, hemorrhagic complications.

June 2013

White C, Gulati M, Gomes A, Rajfer J, Raman S.

PURPOSE: High-flow priapism is often a sequela of perineal trauma resulting in an arteriocavernosal fistula (ACF) between a cavernosal artery and lacunar spaces of the penis. We report our experience utilizing magnetic resonance angiography (MRA) in addition to color Doppler Sonography (CDS) in the workup and treatment planning of 4 patients with high-flow priapism. METHODS: All patients had suspected high-flow priapism diagnosed by clinical exam and CDS and underwent MRA of the penis prior to sub-selective arterial embolization (SSAE) of the feeding vessel(s).

June 2013

Wu W, Tanrivermis Sayit A, Vinters HV, Pope W, Mirsadraei L, Said J.

Histiocytic sarcoma (HS) is a rare neoplasm that occurs most commonly in the intestinal tract, skin, soft tissue, and lymph node. The incidence of primary central nervous system (CNS) HS is even rarer, with a total of 6 cases reported in the literature. An etiologic link has not been identified for CNS HS, and the current case of primary CNS HS is unique in that an etiologic link to prior radiation therapy is identified, associated with complex cytogenetic abnormalities in the tumor. Although radiation-associated sarcomas can present as any number of different pathologic entities, this is the first reported case of a radiation-associated CNS HS. The pathologic and immunophenotypic characteristics of this case, with a nearly obscuring heavy inflammatory infiltrate and expression of monocytic/histiocytic markers (CD163, CD68, CD4, fascin), are characteristic of CNS HS. A discussion of the differential diagnosis and review of relevant literature are presented.

May 2013

Black MT, Hung CA, Loh C.

OBJECTIVE. T-fastener gastropexy is a step in percutaneous radiologic gastrostomy in which the stomach is fastened to the abdominal wall. Minor complications of gastropexy are often related to the prolonged presence of T-fastener sutures. We describe a new technique for gastropexy using absorbable sutures placed subcutaneously, as opposed to the standard percutaneous approach. CONCLUSION. Subcutaneous gastropexy is safe, obviates follow-up suture removal, and eliminates complications associated with cutaneous sutures.

May 2013

Carney PA, Parikh J, Sickles EA, Feig SA, Monsees B, Bassett LW, Smith RA, Rosenberg R, Ichikawa L, Wallace J, Tran K, Miglioretti DL.

PURPOSE: To develop criteria to identify thresholds for the minimally acceptable performance of physicians interpreting diagnostic mammography studies. Materials and Methods: In an institutional review board-approved HIPAA-compliant study, an Angoff approach was used to set criteria for identifying minimally acceptable interpretive performance for both workup after abnormal screening examinations and workup of a breast lump. Normative data from the Breast Cancer Surveillance Consortium (BCSC) was used to help the expert radiologist identify the impact of cut points. Simulations, also using data from the BCSC, were used to estimate the expected clinical impact from the recommended performance thresholds.

May 2013

Frei D, Gerber J, Turk A, McPherson M, Heck D, Hui F, Joseph G, Jahan R, Miskolczi L, Carpenter J, Grobelny T, Goddard J, Turner RD, Huddle D, Bellon R, Chaudry I.

BACKGROUND AND PURPOSE: Revascularization of acute ischemic stroke from a large vessel occlusion continues to be a challenge with current thrombectomy devices. The purpose of the SPEED study was to report the safety and effectiveness of the Penumbra 054 Reperfusion Catheter System in revascularizing large vessel occlusions. METHODS: In this retrospective multicenter study, data were collected from patients with angiographic evidence of large vessel occlusion treated with the Penumbra 054 device as the intended primary therapy. Clinical outcome data were collected with 90-day follow-up and the results were compared with those from the Penumbra Pivotal trial.

May 2013

Fujimoto M, Salamon N, Mayor F, Yuki I, Takemoto K, Vinters HV, Viñuela F.

BACKGROUND AND PURPOSE: The aim of this study is to analyze the histological composition of acute arterial thrombi and their MRI signals. METHODS: Two different types of experimental thrombi, erythrocyte- and fibrin-rich thrombus, were created and injected into an experimentally formed stenotic common carotid artery in swine. MRI of the in vivo and in vitro samples was obtained immediately after the thrombus application.

May 2013

Kim AI, Han SH, Tran DT, Sullivan P, Lassman C, Raman S, Zimmerman P, Chin EE.

Patients with acute liver failure (ALF) can be listed status I for liver transplantation (LT) whereas patients with cirrhosis must follow the MELD scoring system. Liver imaging can mistakenly diagnose submassive hepatic necrosis in ALF as cirrhosis. The purpose of our study was to assess the accuracy of ultrasound (US) and computed tomography (CT) in distinguishing cirrhosis from ALF. All patients listed for ALF and transplanted during the study period were included. Controls were age- and gender-matched cirrhotic patients who underwent LT during the same period. Abdominal US or CT scans obtained on all patients were independently reviewed by three blinded abdominal radiologists. Explants from all patients were reviewed by two blinded pathologists, and histological diagnosis was correlated with radiological diagnosis. Forty-one patients with ALF and 42 patients with cirrhosis were analyzed. Univariate and multivariate analyses both revealed overall accuracy of 85% for ultrasound and 93% for CT. US and CT scans both provide high levels of accuracy in terms of discriminating ALF from cirrhosis but measures taken to determine whether a patient has ALF vs. cirrhosis needs to approach 100% accuracy. Thus, imaging studies alone should not definitively diagnosis one etiology of liver failure over the other.

May 2013

Kim EY, Song HY, Kim JH, Fan Y, Park S, Kim DK, Lee EW, Na HK.

PURPOSE: To investigate the efficacy of an IN-1233-eluting covered stent in preventing tissue hyperplasia in a rabbit esophageal model. MATERIALS AND METHODS: The local animal research committee approved all experiments. Esophageal stents were placed in 40 male New Zealand rabbits (weight range, 2.8-3.2 kg). The drug group (D) received IN-1233-eluting covered stents (n = 20); the control group (C) received polyurethane-covered stents (n = 20). Drug loading of IN-1233-eluting covered stent was 10%. Four study groups were formed: C and D animals sacrificed at 4 (D4, C4) and 8 (D8, C8) weeks after stent placement (n = 10). Esophagography was used to assess the percentage of diameter stenosis. Histologic findings of the drug and control stents were compared. The Mann-Whitney U test was used to evaluate differences.