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Research Publications
Nov 2013
Preclinical Studies of the Role of Iron Oxide Magnetic Nanoparticles for Nonpalpable Lesion Localization in Breast Cancer.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.
Nov 2013
Baseline Regional Perfusion Impacts Exercise Response to Endobronchial Valve Therapy in Advanced Pulmonary Emphysema.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.
Nov 2013
Imaging-Based Observational Databases for Clinical Problem Solving: the Role of Informatics.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.
Nov 2013
Association of Paraoxonase 1 Gene Polymorphism and Enzyme Activity with Carotid Plaque in Rheumatoid Arthritis.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.
Nov 2013
IS FlowMap, a Novel Tool to Examine Blood Flow Changes Induced by Flow Diverter Stent Treatment: Initial Experiences with Pipeline Cases.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.
Nov 2013
Solitary Fibrous Tumor of the Larynx: Case Report Demonstrating the Value of MRI in Guiding Surgical Management.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.
Nov 2013
Direct Thrombus Aspiration Using the Penumbra System for the Treatment of Pediatric Intracranial Dissection.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.
Nov 2013
Efficacy of Imaging-Guided Percutaneous Radiofrequency Ablation for the Treatment of Biopsy-proven Malignant Cystic Renal Masses.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.
Nov 2013
Biomedical Imaging Informatics in the Era of Precision Medicine: Progress, Challenges, and Opportunities.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).
Nov 2013
Endovascular Treatment of Ruptured Dissecting Aneurysms of the Posterior Inferior Cerebellar Artery.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.
Nov 2013
Quantitative Analysis of Hypoperfusion in Acute Stroke: Arterial Spin Labeling Versus Dynamic Susceptibility Contrast.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.
Nov 2013
Delivering High-Quality and Affordable Care Throughout the Cancer Care Continuum.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.
Nov 2013
Intra-Aneurysmal Hemodynamic Alterations by a Self-Expandable Intracranial Stent and Flow Diversion Stent: High Intra-Aneurysmal Pressure Remains Regardless of Flow Velocity Reduction.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
Oct 2013
Peripheral Vascular Disease as Remote Ischemic Preconditioning, for Acute Stroke.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).
Oct 2013
Evaluation of Age-Related Interstitial Myocardial Fibrosis With Cardiac Magnetic Resonance Contrast-Enhanced T1 Mapping: MESA (Multi-Ethnic Study of Atherosclerosis).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.
Oct 2013
Standards of Reporting for MRI-targeted Biopsy Studies (START) of the Prostate: Recommendations from an International Working Group.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).
Oct 2013
Pulmonary Hypertension Complicating Interstitial Lung Disease and COPD.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.
Oct 2013
Impaired Left Ventricular Filling in COPD and Emphysema: Is It the Heart or the Lungs?: The Multi-Ethnic Study of Atherosclerosis COPD Study.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.
Oct 2013
Natural History of Asymptomatic Unruptured Cerebral Aneurysms Evaluated at CT Angiography: Growth and Rupture Incidence and Correlation with Epidemiologic Risk Factors.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).
Oct 2013
Angular Versus Spatial Resolution Trade-Offs for Diffusion Imaging Under Time Constraints.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.
Sept 2013
Results of the Two Incidence Screenings in the National Lung Screening Trial.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.
Sept 2013
ACR Appropriateness Criteria® Chronic Dyspnea: Suspected Pulmonary Origin.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.
Sept 2013
Diffusion Tensor Imaging Detects Microstructural Reorganization in the Brain Associated with Chronic Irritable Bowel Syndrome.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.
Sept 2013
Computed Tomography as a Biomarker in Clinical Trials Imaging.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.
Sept 2013
Ensemble Segmentation for GBM Brain Tumors on MR Images Using Confidence-Based Averaging.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.
Sept 2013
Pure Arterial Malformation of the Posterior Cerebral Artery: Importance of Its Recognition.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.
Sept 2013
Successful Treatment of Extensive Cerebral Venous Sinus Thrombosis Using a Combined Approach with Penumbra Aspiration System and Solitaire FR Retrieval Device.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.
Sept 2013
Estimating Peak Skin and Eye Lens Dose from Neuroperfusion Examinations: Use of Monte Carlo Based Simulations and Comparisons to CTDIvol, AAPM Report No. 111, and ImPACT Dosimetry Tool Values.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.
Aug 2013
Prognostic Value of Myocardial Circumferential Strain for Incident Heart Failure and Cardiovascular Events in Asymptomatic Individuals: the Multi-Ethnic Study of Atherosclerosis.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.
Aug 2013
Fine-Tuning Robot-Assisted Radical Prostatectomy Planning with MRI.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.
Aug 2013
Radiologic Measurement of Submandibular Gland Ptosis.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.
Aug 2013
Transvenous Retrograde Nidus Sclerotherapy Under Controlled Hypotension (TRENSH): Hemodynamic Analysis and Concept Validation in a Pig Arteriovenous Malformation Model.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.
Aug 2013
Transmit B1+ Field Inhomogeneity and T1 Estimation Errors in Breast DCE-MRI at 3 Tesla.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.
Aug 2013
A Swine Model to Analyze Arterial Structural Changes Induced by Mechanical Thrombectomy.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.
Jul 2013
ACR Appropriateness Criteria® Pulmonary Hypertension.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.
Jul 2013
Enlargement of Small, Asymptomatic, Unruptured Intracranial Aneurysms in Patients with No History of Subarachnoid Hemorrhage: the Different Factors Related to the Growth of Single and Multiple Aneurysms.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.
Jul 2013
The Hyperdense Vessel Sign on CT Predicts Successful Recanalization with the Merci Device in Acute Ischemic Stroke.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.
Jul 2013
Simulated Biomechanical Responses at a Curved Arterial Segment After Wingspan Stent Deployment in Swine.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.
Jul 2013
Time to Pediatric Epilepsy Surgery is Longer and Developmental Outcomes Lower for Government Compared With Private Insurance.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.
Jul 2013
Effective Dose Assessment for Participants in the National Lung Screening Trial Undergoing Posteroanterior Chest Radiographic Examinations.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.
Jul 2013
Society of Interventional Radiology Position Statement on Recent Change to the ASA's Moderate Sedation Standards: Capnography.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.
Jul 2013
Standard of Practice: Embolization of Ruptured and Unruptured Intracranial Aneurysms.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
Jul 2013
Three-Phase Parathyroid 4-Dimensional Computed Tomography Initial Experience: Inexperienced Readers Have High Accuracy and High Interobserver Agreement.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.
Jul 2013
Flow Control Techniques for Onyx Embolization of Intracranial Dural Arteriovenous Fistulae.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.
Jul 2013
Novel Aneurysm Neck Reconstruction Device: Initial Experience in an Experimental Preclinical Bifurcation Aneurysm Model.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.
Jun 2013
Functionalized Magnetonanoparticles in Visualization of Intracranial Tumors on MRI.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.
Jun 2013
A Rare Occurrence of Pulmonary Alveolar Proteinosis After Lung Transplantation.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.
Jun 2013
Pediatric Cardiovascular Interventional Devices: Effect on CMR Images at 1.5 and 3 Tesla.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.
Jun 2013
A Dose-Ranging Study of Cabozantinib in Men with Castration-Resistant Prostate Cancer and Bone Metastases.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).
Jun 2013
WEB Device for Endovascular Treatment of Wide-Neck Bifurcation Aneurysms.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.
Jun 2013
Salvage of Free-Flaps in Vessel-depleted Mandibular Osteoradionecrosis Cases Using Catheter-directed Thrombolysis and Angioplasty.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.
Jun 2013
Pre-Embolization Evaluation of High-Flow Priapism: Magnetic Resonance Angiography of the Penis.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).
Jun 2013
Primary Central Nervous System Histiocytic Sarcoma Presenting as a Postradiation Sarcoma: Case Report and Literature Review.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
Subcutaneous T-Fastener Gastropexy: a New Technique.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
Diagnostic Mammography: Identifying Minimally Acceptable Interpretive Performance Criteria.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
The SPEED Study: Initial Clinical Evaluation of the Penumbra Novel 054 Reperfusion Catheter.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
Characterization of Arterial Thrombus Composition by Magnetic Resonance Imaging in a Swine Stroke Model.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
Abdominal Imaging can Misdiagnose Submassive Hepatic Necrosis as Cirrhosis in Acute Liver Failure.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
IN-1233-Eluting Covered Metallic Stent to Prevent Hyperplasia: Experimental Study in a Rabbit Esophageal Model.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.
May 2013
Incomplete Mechanical Recanalization of Middle Cerebral Artery Occlusions Facilitates Endogenous Recanalization within 5 h.BACKGROUND AND PURPOSE: Successful revascularization can often improve functional outcome after large intracranial arterial occlusions. However, incomplete or unsuccessful recanalization is often the end result after attempted mechanical thrombectomy. A study was undertaken to determine whether partial recanalization of proximal isolated middle cerebral artery (MCA) occlusions facilitates endogenous thrombolysis and spontaneous recanalization. METHODS: We retrospectively analyzed consecutive patients with acute ischemic stroke undergoing mechanical thrombectomy using the Merci Retriever System for occlusions involving any portion of the M1 segment of the MCA. Only those patients with a residual obstruction of the proximal MCA segments were included. The rates of facilitated endogenous recanalization (FER₅) by imaging within the 5 h following intervention were compared in patients with partial proximal recanalization and those in whom recanalization was unsuccessful.
May 2013
Identifying the Mesenchymal Molecular Subtype of Glioblastoma Using Quantitative Volumetric Analysis of Anatomic Magnetic Resonance Images.BACKGROUND: Subtypes of glioblastoma multiforme (GBM) based on genetic and molecular alterations are thought to cause alterations in anatomic MRI owing to downstream biological changes, such as edema production, blood-brain barrier breakdown, and necrosis. The purpose of the current study was to identify a potential relationship between imaging features and the mesenchymal (MES) GBM subtype, which has the worst patient prognosis. METHODS: MRIs from 46 patients with histologically confirmed GBM were retrospectively analyzed. The volume of contrast enhancement, regions of central necrosis, and hyperintensity of T2/fluid attenuated inversion recovery (FLAIR) were measured. Additionally, the ratio of T2/FLAIR hyperintense volume to the volume of contrast enhancement and necrosis was calculated.
May 2013
Results of Initial Low-Dose Computed Tomographic Screening for Lung Cancer.BACKGROUND: Lung cancer is the largest contributor to mortality from cancer. The National Lung Screening Trial (NLST) showed that screening with low-dose helical computed tomography (CT) rather than with chest radiography reduced mortality from lung cancer. We describe the screening, diagnosis, and limited treatment results from the initial round of screening in the NLST to inform and improve lung-cancer-screening programs. METHODS: At 33 U.S. centers, from August 2002 through April 2004, we enrolled asymptomatic participants, 55 to 74 years of age, with a history of at least 30 pack-years of smoking. The participants were randomly assigned to undergo annual screening, with the use of either low-dose CT or chest radiography, for 3 years. Nodules or other suspicious findings were classified as positive results. This article reports findings from the initial screening examination.
May 2013
Clear Cell Renal Cell Carcinoma: Discrimination from Other Renal Cell Carcinoma Subtypes and Oncocytoma at Multiphasic Multidetector CT.PURPOSE: To determine whether enhancement at multiphasic multidetector computed tomography (CT) can help differentiate clear cell renal cell carcinoma (RCC) from oncocytoma, papillary RCC, and chromophobe RCC. MATERIALS AND METHODS: With institutional review board approval for this HIPAA-compliant retrospective study, the pathology database was queried to derive a cohort of 298 cases of RCC and oncocytoma with preoperative multiphasic multidetector CT with as many as four phases (unenhanced, corticomedullary, nephrographic, and excretory). A total of 170 clear cell RCCs, 57 papillary RCCs, 49 oncocytomas, and 22 chromophobe RCCs were evaluated for multiphasic enhancement and compared by using t tests. Cutoff analysis was performed to determine optimal threshold levels to discriminate among the four groups.
Apr 2013
Doppler US for Suspicion of Hepatic Arterial Ischemia in Orthotopically Transplanted Livers: Role of Central versus Intrahepatic Waveform Analysis.PURPOSE: To compare the diagnostic performance of combinations of parameters derived from main hepatic artery (MHA) and intrahepatic artery (IHA) waveforms at Doppler ultrasonography (US), with the aim of developing a systematic approach to the evaluation of the hepatic arteries in orthotopic liver transplants in patients suspected of having hepatic arterial ischemia. Materials and METHODS: This HIPAA-compliant retrospective study was approved by an institutional review board, with waiver of informed consent. From January 1, 2002, to November 1, 2011, 195 transplanted livers in 189 adults (129 men, 60 women; mean age, 53 years; age range, 18-73 years) who underwent Doppler US and follow-up (computed tomographic, magnetic resonance, or conventional) angiographic study within a 2-week interval were included. Diagnostic performance of the standard IHA and MHA criteria (resistive index [RI] < 0.5 and classic parvus tardus waveforms) with and without peak systolic velocity (PSV) thresholds (determined with receiver operating characteristic curve analysis) was assessed. The results of no-flow analysis and the most optimal MHA and IHA criteria were combined to create an algorithm, which was then applied to all liver transplants.
Apr 2013
Pre- and Post-Contrast Three-Dimensional Double Inversion-Recovery MRI in Human Glioblastoma.Fluid attenuated inversion recovery (FLAIR) MRI sequences have become an indispensible tool for defining the malignant boundary in patients with brain tumors by nulling the signal contribution from cerebrospinal fluid allowing both regions of edema and regions of non-enhancing, infiltrating tumor to become hyperintense on resulting images. In the current study we examined the utility of a three-dimensional double inversion recovery (DIR) sequence that additionally nulls the MR signal associated with white matter, implemented either pre-contrast or post-contrast, in order to determine whether this sequence allows for better differentiation between tumor and normal brain tissue. T1- and T2-weighted, FLAIR, dynamic susceptibility contrast (DSC)-MRI estimates of cerebral blood volume (rCBV), contrast-enhanced T1-weighted images (T1+C), and DIR data (pre- or post-contrast) were acquired in 22 patients with glioblastoma. Contrast-to-noise (CNR) and tumor volumes were compared between DIR and FLAIR sequences. Line profiles across regions of tumor were generated to evaluate similarities between image contrasts. Additionally, voxel-wise associations between DIR and other sequences were examined. Results suggested post-contrast DIR images were hyperintense (bright) in regions spatially similar those having FLAIR hyperintensity and hypointense (dark) in regions with contrast-enhancement or elevated rCBV due to the high sensitivity of 3D turbo spin echo sequences to susceptibility differences between different tissues. DIR tumor volumes were statistically smaller than tumor volumes as defined by FLAIR (Paired t test, P = 0.0084), averaging a difference of approximately 14 mL or 24 %. DIR images had approximately 1.5x higher lesion CNR compared with FLAIR images (Paired t test, P = 0.0048). Line profiles across tumor regions and scatter plots of voxel-wise coherence between different contrasts confirmed a positive correlation between DIR and FLAIR signal intensity and a negative correlation between DIR and both post-contrast T1-weighted image signal intensity and rCBV. Additional discrepancies between FLAIR and DIR abnormal regions were also observed, together suggesting DIR may provide additional information beyond that of FLAIR.
Apr 2013
Dyspepsia: Structural Changes in Functional Gastrointestinal Disorders.Functional gastrointestinal disorders (FGIDs) are currently defined on the basis of characteristic symptom patterns in patients with chronic abdominal discomfort or pain in the absence of biochemical or structural changes that might explain the symptoms. Now, for the first time, a study by Zhou et al.1 has provided evidence for extensive white matter alterations in a group of patients with functional dyspepsia.
Apr 2013
Effects of Intensive Cognitive-Behavioral Therapy on Cingulate Neurochemistry in Obsessive-Compulsive Disorder.The neurophysiological bases of cognitive-behavioral therapy (CBT) for obsessive-compulsive disorder (OCD) are incompletely understood. Previous studies, though sparse, implicate metabolic changes in pregenual anterior cingulate cortex (pACC) and anterior middle cingulate cortex (aMCC) as neural correlates of response to CBT. The goal of this pilot study was to determine the relationship between levels of the neurochemically interlinked metabolites glutamate + glutamine (Glx) and N-acetyl-aspartate + N-acetyl-aspartyl-glutamate (tNAA) in pACC and aMCC to pretreatment OCD diagnostic status and OCD response to CBT. Proton magnetic resonance spectroscopic imaging ((1)H MRSI) was acquired from pACC and aMCC in 10 OCD patients at baseline, 8 of whom had a repeat scan after 4 weeks of intensive CBT. pACC was also scanned (baseline only) in 8 age-matched healthy controls. OCD symptoms improved markedly in 8/8 patients after CBT. In right pACC, tNAA was significantly lower in OCD patients than controls at baseline and then increased significantly after CBT. Baseline tNAA also correlated with post-CBT change in OCD symptom severity. In left aMCC, Glx decreased significantly after intensive CBT. These findings add to evidence implicating the pACC and aMCC as loci of the metabolic effects of CBT in OCD, particularly effects on glutamatergic and N-acetyl compounds. Moreover, these metabolic responses occurred after just 4 weeks of intensive CBT, compared to 3 months for standard weekly CBT. Baseline levels of tNAA in the pACC may be associated with response to CBT for OCD. Lateralization of metabolite effects of CBT, previously observed in subcortical nuclei and white matter, may also occur in cingulate cortex. Tentative mechanisms for these effects are discussed. Comorbid depressive symptoms in OCD patients may have contributed to metabolite effects, although baseline and post-CBT change in depression ratings varied with choline-compounds and myo-inositol rather than Glx or tNAA.
Apr 2013
Pulmonary Hyperinflation and Left Ventricular Mass: The Multi-Ethnic Study of Atherosclerosis COPD Study.BACKGROUND: Left ventricular (LV) mass is an important predictor of heart failure and cardiovascular mortality, yet determinants of LV mass are incompletely understood. Pulmonary hyperinflation in chronic obstructive pulmonary disease (COPD) may contribute to changes in intrathoracic pressure that increase LV wall stress. We therefore hypothesized that residual lung volume in COPD would be associated with greater LV mass. METHODS AND RESULTS: The Multi-Ethnic Study of Atherosclerosis (MESA) COPD Study recruited smokers 50 to 79 years of age who were free of clinical cardiovascular disease. LV mass was measured by cardiac magnetic resonance. Pulmonary function testing was performed according to guidelines. Regression models were used to adjust for age, sex, body size, blood pressure, and other cardiac risk factors. Among 119 MESA COPD Study participants, the mean age was 69±6 years, 55% were male, and 65% had COPD, mostly of mild or moderate severity. Mean LV mass was 128±34 g. Residual lung volume was independently associated with greater LV mass (7.2 g per 1-SD increase in residual volume; 95% confidence interval, 2.2-12; P=0.004) and was similar in magnitude to that of systolic blood pressure (7.6 g per 1-SD increase in systolic blood pressure; 95% confidence interval, 4.3-11; P<0.001). Similar results were observed for the ratio of LV mass to end-diastolic volume (P=0.02) and with hyperinflation measured as residual volume to total lung capacity ratio (P=0.009).
Apr 2013
1H MRSI of Middle Frontal Gyrus in Pediatric ADHD.Neuroimaging studies in multiple modalities have implicated the left or right dorsolateral prefrontal cortex (here, middle frontal gyrus) in attentional functions, in ADHD, and in dopamine agonist treatment of ADHD. The far lateral location of this cortex in the brain, however, has made it difficult to study with magnetic resonance spectroscopy (MRS). We used the smaller voxel sizes of the magnetic resonance spectroscopic imaging (MRSI) variant of MRS, acquired at a steep coronal-oblique angle to sample bilateral middle frontal gyrus in 13 children and adolescents with ADHD and 13 age- and sex-matched healthy controls. Within a subsample of the ADHD patients, aspects of attention were also assessed with the Trail Making Task. In right middle frontal gyrus only, mean levels of N-acetyl-aspartate + N-acetyl-aspartyl-glutamate (tNAA), creatine + phosphocreatine (Cr), choline-compounds (Cho), and myo-inositol (mI) were significantly lower in the ADHD than in the control sample. In the ADHD patients, lower right middle frontal Cr was associated with worse performance on Trails A and B (focused attention, concentration, set-shifting), while the opposite relationship held true for the control group on Trails B. These findings add to evidence implicating right middle frontal cortex in ADHD. Lower levels of these multiple species may reflect osmotic adjustment to elevated prefrontal cortical perfusion in ADHD and/or a previously hypothesized defect in astrocytic production of lactate in ADHD resulting in decelerated energetic metabolism (Cr), membrane synthesis (Cho, mI), and acetyl-CoA substrate for NAA synthesis. Lower Cr levels may indicate attentional or executive impairments.
Mar 2013
Computed Tomography Screening for Lung Cancer: Has it Finally Arrived? Implications of the National Lung Screening Trial.The National Lung Screening Trial (NLST) has provided compelling evidence of the efficacy of lung cancer screening using low-dose helical computed tomography (LDCT) to reduce lung cancer mortality. The NLST randomized 53,454 older current or former heavy smokers to receive LDCT or chest radiography (CXR) for three annual screens. Participants were observed for a median of 6.5 years for outcomes. Vital status was available in more than 95% of participants. LDCT was positive in 24.2% of screens, compared with 6.9% of CXRs; more than 95% of all positive LDCT screens were not associated with lung cancer. LDCT detected more than twice the number of early-stage lung cancers and resulted in a stage shift from advanced to early-stage disease. Complications of LDCT screening were minimal. Lung cancer-specific mortality was reduced by 20% relative to CXR; all-cause mortality was reduced by 6.7%. The major harms of LDCT are radiation exposure, high false-positive rates, and the potential for overdiagnosis. This review discusses the risks and benefits of LDCT screening as well as an approach to LDCT implementation that incorporates systematic screening practice with smoking cessation programs and offers opportunities for better determination of appropriate risk cohorts for screening and for better diagnostic prediction of lung cancer in the setting of screen-detected nodules. The challenges of implementation are considered for screening programs, for primary care clinicians, and across socioeconomic strata. Considerations for future research to complement imaging-based screening to reduce the burden of lung cancer are discussed.
Mar 2013
ACR Appropriateness Criteria Routine Chest Radiographs in Intensive Care Unit Patients.Daily routine chest radiographs in the intensive care unit (ICU) have been a tradition for many years. Anecdotal reports of misplacement of life support items, acute lung processes, and extra pulmonary air collections in a small number of patients served as a justification for routine chest radiographs in the ICU. Having analyzed this practice, the ACR Appropriateness Criteria Expert Panel on Thoracic Imaging has made the following recommendations:
- When monitoring a stable patient or a patient on mechanical ventilation in the ICU, a portable chest radiograph is appropriate for clinical indications only.
- It is appropriate to obtain a chest radiograph after placement of an endotracheal tube, central venous line, Swan-Ganz catheter, nasogastric tube, feeding tube, or chest tube.
Mar 2013
Time to Pediatric Epilepsy Surgery is Related to Disease Severity and Nonclinical Factors.OBJECTIVE: To identify clinical and nonclinical factors associated with time from epilepsy onset to surgical evaluation and treatment among a cohort of children having epilepsy surgery. METHODS: Data were abstracted from records of 430 children (younger than 18 years) who had epilepsy neurosurgery at the University of California, Los Angeles from 1986 to 2010. Multivariable Cox proportional hazards models were used to analyze unique associations of clinical severity, pre-referral brain MRI, and sociodemographic characteristics with time to surgery.
Mar 2013
Percutaneous Image-Guided Cryoablation of Painful Metastases Involving Bone: Multicenter Trial.BACKGROUND: This study sought to describe the results of a single-arm multicenter clinical trial using image-guided percutaneous cryoablation for the palliation of painful metastatic tumors involving bone. METHODS: Over a 44-month period, 61 adult patients with 1 or 2 painful bone metastases with a score of 4 or more on a scale of 0 to 10 (≥4/10) worst pain in a 24-hour period who had failed or refused conventional treatment were treated with percutaneous image-guided cryoablation. Patient pain and quality of life was measured using the Brief Pain Inventory prior to treatment, 1 and 4 days after the procedure, weekly for 4 weeks, and every 2 weeks thereafter for a total of 6 months. Patient analgesic use was also recorded at these same follow-up intervals. Complications were monitored. Analysis of the primary endpoint was undertaken via paired comparison procedures.
Mar 2013
Quantitative Probabilistic Functional Diffusion Mapping in Newly Diagnosed Glioblastoma Treated with Radiochemotherapy.BACKGROUND: Functional diffusion mapping (fDM) is a cancer imaging technique that uses voxel-wise changes in apparent diffusion coefficients (ADC) to evaluate response to treatment. Despite promising initial results, uncertainty in image registration remains the largest barrier to widespread clinical application. The current study introduces a probabilistic approach to fDM quantification to overcome some of these limitations. METHODS: A total of 143 patients with newly diagnosed glioblastoma who were undergoing standard radiochemotherapy were enrolled in this retrospective study. Traditional and probabilistic fDMs were calculated using ADC maps acquired before and after therapy. Probabilistic fDMs were calculated by applying random, finite translational, and rotational perturbations to both pre-and posttherapy ADC maps, then repeating calculation of fDMs reflecting changes after treatment, resulting in probabilistic fDMs showing the voxel-wise probability of fDM classification. Probabilistic fDMs were then compared with traditional fDMs in their ability to predict progression-free survival (PFS) and overall survival (OS).
Mar 2013
Probabilistic Radiographic Atlas of Glioblastoma Phenotypes.BACKGROUND AND PURPOSE: Tumor location is a significant prognostic factor in glioblastoma, which may reflect the genetic profile of tumor precursor cells. The purpose of the current study was to construct and analyze probabilistic radiographic atlases reflecting preoperative tumor locations and corresponding demographic, "-omic," and interventional phenotypes to provide insight into potential niche locations of glioblastoma cells of origin. MATERIALS AND METHODS: Preoperative anatomic MR images in 507 patients with de novo glioblastoma were analyzed. Images were registered to stereotactic space, tumors were segmented, and the stereospecific frequency of tumor occurrence was analyzed statistically by age, extent of resection, MGMT methylation, IDH1 mutation, gene expression subclassification, PTEN loss, PTEN deficiency, EGFR amplification, EGFR variant 3 expression, progression-free survival from the start of radiochemotherapy, and overall survival from initial diagnosis.
Mar 2013
Analysis of Radiology Business Models.As health care moves to value orientation, radiology's traditional business model faces challenges to adapt. The authors describe a strategic value framework that radiology practices can use to best position themselves in their environments. This simplified construct encourages practices to define their dominant value propositions. There are 3 main value propositions that form a conceptual triangle, whose vertices represent the low-cost provider, the product leader, and the customer intimacy models. Each vertex has been a valid market position, but each demands specific capabilities and trade-offs. The underlying concepts help practices select value propositions they can successfully deliver in their competitive environments.
Mar 2013
Sociodemographic Changes Over 25 Years of Pediatric Epilepsy Surgery at UCLA.Object Low income, government insurance, and minority status are associated with delayed treatment for neurosurgery patients. Less is known about the influence of referral location and how socioeconomic factors and referral patterns evolve over time. For pediatric epilepsy surgery patients at the University of California, Los Angeles (UCLA), this study determined how referral location and sociodemographic features have evolved over 25 years. Methods Children undergoing epilepsy neurosurgery at UCLA (453 patients) were classified by location of residence and compared with clinical epilepsy and sociodemographic factors. Results From 1986 to 2010, referrals from Southern California increased (+33%) and referrals from outside of California decreased (-19%). Over the same period, the number of patients with preferred provider organization (PPO) and health maintenance organization (HMO) insurance increased (+148% and +69%, respectively) and indemnity insurance decreased (-96%). Likewise, the number of Hispanics (+117%) and Asians (100%) increased and Caucasians/whites decreased (-24%). The number of insurance companies decreased from 52 carriers per 100 surgical patients in 1986-1990 to 19 per 100 in 2006-2010. Patients living in the Eastern US had a younger age at surgery (-46%), shorter intervals from seizure onset to referral for evaluation (-28%) and from presurgical evaluation to surgery (-61%) compared with patients from Southern California. The interval from seizure onset to evaluation was shorter (-33%) for patients from Los Angeles County compared with those living in non-California Western US states. Conclusions Referral locations evolved over 25 years at UCLA, with more cases coming from local regions; the percentage of minority patients also increased. The interval from seizures onset to surgery was shortest for patients living farthest from UCLA but still within the US. Geographic location and race/ethnicity was not associated with differences in becoming seizure free after epilepsy surgery in children.
Mar 2013
A Trial of Imaging Selection and Endovascular Treatment for Ischemic Stroke.BACKGROUND: Whether brain imaging can identify patients who are most likely to benefit from therapies for acute ischemic stroke and whether endovascular thrombectomy improves clinical outcomes in such patients remains unclear. METHODS: In this study, we randomly assigned patients within 8 hours after the onset of large-vessel, anterior-circulation strokes to undergo mechanical embolectomy (Merci Retriever or Penumbra System) or receive standard care. All patients underwent pretreatment computed tomography or magnetic resonance imaging of the brain. Randomization was stratified according to whether the patient had a favorable penumbral pattern (substantial salvageable tissue and small infarct core) or a nonpenumbral pattern (large core or small or absent penumbra). We assessed outcomes using the 90-day modified Rankin scale, ranging from 0 (no symptoms) to 6 (dead).
Mar 2013
Combined Analysis of O6-Methylguanine-DNA Methyltransferase Protein Expression and Promoter Methylation Provides Optimized Prognostication of Glioblastoma Outcome.BACKGROUND: Promoter methylation of the DNA repair gene, O-6-methylguanine-DNA methyltransferase (MGMT), is associated with improved treatment outcome for newly diagnosed glioblastoma (GBM) treated with standard chemoradiation. To determine the prognostic significance of MGMT protein expression as assessed by immunohistochemistry (IHC) and its relationship with methylation, we analyzed MGMT expression and promoter methylation with survival in a retrospective patient cohort. METHODS: We identified 418 patients with newly diagnosed GBM at University of California Los Angeles Kaiser Permanente Los Angeles, nearly all of whom received chemoradiation, and determined MGMT expression by IHC, and MGMT promoter methylation by methylation-specific PCR (MSP) and bisulfite sequencing (BiSEQ) of 24 neighboring CpG sites.
Mar 2013
Irreversible Electroporation in Porcine Liver: Acute Computed Tomography Appearance of Ablation Zone with Histopathologic Correlation.OBJECTIVE: The objective of this study was to define acute computed tomography (CT) characteristics of ablation zone created by irreversible electroporation (IRE) in porcine liver, with histopathologic correlation. METHODS: Twenty-three IRE ablation zones were created in 4 Yorkshire pig livers percutaneously under image guidance. A prototype generator was used (Ethicon Endo-surgery, Cincinnati, Ohio). Variable spacing of paired electrodes between 1 and 2.0 cm was used. Contrast-enhanced multiphasic CT scans were obtained. Pigs were killed after 5 to 6 hours for gross pathology sectioning with routine and vital histological stains. Computed tomography images were analyzed using 3-dimensional software, and ablation zone size measured on CT was correlated with pathologically determined size.
Mar 2013
Stress Fracture of the Scapula in a Professional Baseball Pitcher: Case Report and Review of the Literature.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 2013
Complete Tumor Encapsulation on Magnetic Resonance Imaging: A Potentially Useful Imaging Biomarker for Better Survival in Solitary Large Hepatocellular Carcinoma.The aim of this study was to determine the prognostic value of complete tumor encapsulation as visualized on magnetic resonance imaging (MRI) in patients with a solitary large hepatocellular carcinoma (HCC) beyond the Milan criteria for liver transplantation (LT). Between December 2000 and March 2011, 57 patients who had a solitary HCC exceeding 5 cm in diameter at the time of initial MRI before any treatment were identified. MRI images of the patients were independently reviewed by 2 experienced readers for the presence of complete tumoral encapsulation. The medical records of the patients were reviewed for an outcome analysis. Thirty of the 57 patients had completely encapsulated HCC according to MRI. There was excellent interobserver agreement between the 2 readers for the assessment of complete encapsulation (K=0.86). Overall survival was significantly longer for patients with completely encapsulated HCC versus patients with incompletely or nonencapsulated tumors (P<0.001), and this included a subanalysis of 33 patients who received locoregional treatment (LRT; P=0.04). The presence of complete encapsulation was a strong predictor for survival in these patients according to both univariate [hazard ratio (HR)=0.24, 95% confidence interval (CI)=0.12-0.52, P<0.001] and multivariate analyses (HR=0.25, 95% CI=0.07-0.85, P=0.03). The rates of down-staging (P<0.001) and eventual LT (P=0.02) after LRT were also significantly higher in the patients with completely encapsulated tumors. In conclusion, complete tumor encapsulation on MRI is a potentially useful predictor for favorable biology in patients with a solitary large HCC. This new imaging biomarker may have a role in treatment selection for patients whose tumors exceed the Milan criteria size limits.
Mar 2013
An Infundibulum of Thalamoperforator Arteries: Importance of Angiographic Images for Appropriate Diagnosis.BACKGROUND: The identification of infundibula on noninvasive imaging modalities may be challenging. Because these lesions have generally been viewed as nonpathological, distinguishing them from small or micro-aneurysms is important. CASE DESCRIPTION: A 39-year-old male was diagnosed with recurrence of typical orgasmic headache. An outpoutching arising from the distal part of the right P1 at the take-off of thalamoperforator arteries was visualized on noninvasive investigations. The patient was referred to neurosurgery for surgical management of a right P1 aneurysm. Its unusual location and morphology led to be suspicious of an infundibular dilatation. Catheter angiography with 2D projections and 3D rotational reconstruction revealed an infundibulum at the common origin of two thalamoperforators, giving rise to a double-peaked shape, mimicking a true aneurysm, rather than the more characteristic conical shape of an infundibulum.
Mar 2013
Periprocedural Arterial Spin Labeling and Dynamic Susceptibility Contrast Perfusion in Detection of Cerebral Blood Flow in Patients with Acute Ischemic Syndrome.BACKGROUND AND PURPOSE: To compare the diagnostic performance of arterial spin-labeling (ASL) and dynamic susceptibility contrast (DSC) perfusion in detecting cerebral blood flow (CBF) changes before and after endovascular recanalization in acute ischemic syndrome. METHODS: The inclusion criteria for this retrospective study were patients with acute ischemic syndrome who underwent endovascular recanalization and acquisition of both ASL and DSC before and after revascularization. ASL-CBF and multiparametric DSC maps were evaluated for image quality, location, and type of perfusion abnormality. Relative CBF (rCBF) was calculated in the infarction core and hypoperfused areas using coregistered ASL and DSC. Core and hypoperfused rCBF were used for paired pretreatment and posttreatment comparisons. Interobserver and intermodality agreement were evaluated by K test, and t test was calculated for ASL and DSC rCBF values.
Mar 2013
Quantitative Assessment of Systolic and Diastolic Left Ventricular Twist Using Fourier Analysis of Stimulated Echoes (FAST) and CSPAMM.PURPOSE: To evaluate Fourier Analysis of Stimulated echoes (FAST) and CSPAMM 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 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.
Mar 2013
Onyx embolization of anterior condylar confluence dural arteriovenous fistula.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 2013
Cardiac Dual-Source CT for the Preoperative Assessment of Patients Undergoing Bariatric Surgery.AIM: To assess the diagnostic value of coronary dual-source computed tomography (DSCT) as a comprehensive, non-invasive tool in the preoperative cardiac evaluation of patients undergoing bariatric surgery. MATERIALS AND METHODS: Thirty consecutive obese [average body mass index (BMI): 45 ± 7.6, range: 35-59] patients (24 women; six men; median age: 52 ± 15 years) were enrolled in this institutional review board (IRB)-approved, Health Insurance Portability and Accountability Act of 1996 (HIPAA)-compliant prospective study. Calcium scoring (CaS) and electrocardiography (ECG)-gated images of the coronary arteries were obtained with a large body habitus protocol (120 kV; 430 mAs; 100 ml iodinated contrast medium at 7 ml/s injection rate) on a DSCT machine. Qualitative (four-point: 1 = excellent to 4 = not delineable) coronary segmental analysis, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) measurements were performed. The presence and degree of vascular disease (four-grade scale: mild to severe) was correlated with CaS and cardiovascular (CV) risk stratification blood tests. In patients with severe stenosis (>70%), findings were compared with cardiac nuclear medicine imaging (single photon-emission computed tomography; SPECT) imaging.
Feb 2013
Quantitative Comparison of the Dynamic Flow Waveform Changes in 12 Ruptured and 29 Rnruptured ICA-Ophthalmic Artery Aneurysms.INTRODUCTION: Studies have reported a correlation between blood flow dynamics in the cardiac cycle and vascular diseases, but research to analyze the dynamic changes of flow in cerebral aneurysms is limited. This quantitative study investigates the temporal changes in flow during a cardiac cycle (flow waveform) in different regions of aneurysms and their association with aneurysm rupture. METHODS: Twelve ruptured and 29 unruptured aneurysms from the internal carotid artery–ophthalmic artery segment were studied. Patient-specific aneurysm data were implemented to simulate blood flow. The temporal flow changes at different regions of the aneurysm were recorded to compare the flow waveforms.
Feb 2013
Middle Cranial Fossa Sphenoidal Region Dural Arteriovenous Fistulas: Anatomic and Treatment Considerations.BACKGROUND AND PURPOSE: DAVFs rarely involve the sphenoid wings and middle cranial fossa. We characterize the angiographic findings, treatment, and outcome of DAVFs within the sphenoid wings. MATERIALS AND METHODS: We reviewed the clinical and radiologic data of 11 patients with DAVFs within the sphenoid wing that were treated with an endovascular or with a combined endovascular and surgical approach.
Feb 2013
Vein of Galen Malformation with Cutaneous Signs.Cutaneous vascular malformations may be the presenting sign of more serious internal abnormalities. This case of vein of Galen malformation (VGAM) illustrates the importance of obtaining imaging studies in select cases.
Jan 2013
Radiologic Implications of the 2011 Classification of Adenocarcinoma of the Lung.Now the leading subtype of lung cancer, adenocarcinoma received a new classification in 2011. For tumors categorized previously as bronchioloalveolar carcinoma (BAC), criteria and terminology had not been uniform, so the 2011 classification provided four new terms: (a) adenocarcinoma in situ (AIS), representing histopathologically a small (≤3-cm), noninvasive lepidic growth, which at computed tomography (CT) is usually nonsolid; (b) minimally invasive adenocarcinoma, representing histopathologically a small (≤3-cm) and predominantly lepidic growth that has 5-mm or smaller invasion, which at CT is mainly nonsolid but may have a central solid component of up to approximately 5 mm; (c) lepidic predominant nonmucinous adenocarcinoma, representing histopathologically invasive adenocarcinoma that shows predominantly lepidic nonmucinous growth, which at CT is usually part solid but may be nonsolid or occasionally have cystic components; and (d) invasive mucinous adenocarcinoma, histopathologically showing lepidic growth as its predominant component, which at CT varies widely from solid to mostly solid to part solid to nonsolid and may be single or multiple (when multifocal, it was formerly called multicentric BAC). In addition, new histopathologic subcategories of acinar, papillary, micropapillary, and solid predominant adenocarcinoma are now described, all as nonmucinous, predominantly invasive, may include a small lepidic component, and at CT are usually solid but may include a small nonsolid component. The micropapillary subtype has a poorer prognosis than the other subtypes. In addition, molecular genetic correlations for the subcategories of adenocarcinoma of the lung are now a topic of increasing interest. As the new classification enters common use, further descriptions of related correlations can be anticipated. © RSNA, 2012.
Jan 2013
TIPS Placement via Combined Transjugular and Transhepatic Approach for Cavernous Portal Vein Occlusion: Targeted Approach.Purpose. We report a novel technique which aided recanalization of an occluded portal vein for transjugular intrahepatic portosystemic shunt (TIPS) creation in a patient with symptomatic portal vein thrombosis with cavernous transformation. Some have previously considered cavernous transformation a contraindication to TIPS. Case Presentation. 62-year-old man with chronic pancreatitis, portal vein thrombosis, portal hypertension and recurrent variceal bleeding presents with melena and hematemesis. The patient was severely anemic, hemodynamically unstable, and required emergent portal decompression. Attempts to recanalize the main portal vein using traditional transjugular access were unsuccessful. After percutaneous transhepatic right portal vein access and navigation of a wire through the occluded main portal vein, an angioplasty balloon was inflated at the desired site of shunt takeoff. The balloon was targeted and punctured from the transjugular approach, and a wire was passed into the portal system. TIPS placement then proceeded routinely. Conclusion. Although occlusion of the portal vein increases difficulty of performing TIPS, it should not be considered an absolute contraindication. We have described a method for recanalizing an occluded portal vein using a combined transhepatic and transjugular approach for TIPS. This approach may be useful to relieve portal hypertension in patients who fail endoscopic and/or surgical therapies.
Jan 2013
ACR Appropriateness Criteria® Radiographically Detected Solitary Pulmonary Nodule.The solitary pulmonary nodule (SPN) is a common medical problem for which management can be quite complex. Imaging remains at the center of management of SPNs, and computed tomography is the primary modality by which SPNs are characterized and followed up for stability. This manuscript summarizes the American College of Radiology Appropriateness Criteria for radiographically detected solitary pulmonary nodules and briefly reviews the various imaging techniques available. 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.
Jan 2013
Multiparametric MRI and CT Models of Infarct Core and Favorable Penumbral Imaging Patterns in Acute Ischemic Stroke.BACKGROUND AND PURPOSE: Objective imaging methods to identify optimal candidates for late recanalization therapies are needed. The study goals were (1) to develop magnetic resonance imaging (MRI) and computed tomography (CT) multiparametric, voxel-based predictive models of infarct core and penumbra in acute ischemic stroke patients, and (2) to develop patient-level imaging criteria for favorable penumbral pattern based on good clinical outcome in response to successful recanalization. METHODS: An analysis of imaging and clinical data was performed on 2 cohorts of patients (one screened with CT, the other with MRI) who underwent successful treatment for large vessel, anterior circulation stroke. Subjects were divided 2:1 into derivation and validation cohorts. Pretreatment imaging parameters independently predicting final tissue infarct and final clinical outcome were identified.
Jan 2013
Cost Minimization Analysis of Ultrasound-Guided Diagnostic Evaluation of Probably Benign Breast Lesions.The objective of this study was to compare direct health care costs for two competing diagnostic strategies for probably benign breast lesions detected by ultrasound in young women. We developed a decision analytic model and performed a cost minimization analysis comparing ultrasound-guided vacuum-assisted core biopsy and conservative short-term diagnostic ultrasound follow-up. Relative probabilities for diagnostic outcomes were derived from pooled analysis of the medical literature. Direct health care costs were estimated using United States national average figures from calendar year 2010. Deterministic sensitivity analyses were conducted, as well as a first-order Monte Carlo simulation to confirm cost differences between the two strategies. The conservative short-term imaging follow-up strategy ($639.55 average cost per patient) was the most economical strategy compared to immediate vacuum-assisted core biopsy ($879.55 average cost per patient). Sensitivity analyses demonstrated that the preferred strategy is most dependent on the probabilities of detecting change in appearance on follow-up ultrasound, having a benign finding on immediate core biopsy, and finding cancer on a biopsy triggered by an interval change in ultrasound appearance. The model was also sensitive to the costs of vacuum-assisted core biopsy and diagnostic ultrasound. Conservative imaging follow-up of BIRADS 3 breast masses by ultrasound is cost saving compared to immediate vacuum-assisted core biopsy, with a potential of saving more than one-third of overall costs associated with the diagnostic work-up of such lesions. Watchful waiting with short-term interval follow-up ultrasounds will spare women from unnecessary procedures and spare the United States health care system from unnecessary direct health care costs.
Jan 2013
An Extensive Stanford Type a Aortic Dissection Involving Bilateral Carotid and Iliac Arteries.We present a rare case of continuous, extensive aortic dissection (AD) involving the bilateral common carotid arteries, the ascending, thoracic, and abdominal aorta, and bifurcation of the right common iliac artery. A 61-year-old man with history of chronic hypertension presented with a one-day history of chest pain, vertigo, left facial drooping, and left hemiparesis. Despite the presence of bilateral carotid bruits, doppler ultrasound of the neck was postponed, and the patient was treated with thrombolytic therapy for a presumed ischemic stroke. The patient's symptoms began to resolve within an hour of treatment, at which time treatment was withheld. Ultrasound performed the following day showed dissection of bilateral common carotid arteries, and CT angiography demonstrated extensive AD as described earlier. The patient subsequently underwent cardiovascular surgery and has been doing clinically well since then. AD has a myriad of manifestations depending on the involvement of aortic branches. Our paper illustrates the importance of having a high index of suspicion for AD when a patient presents with a picture of ischemic stroke, since overlapping signs and symptoms exist between AD and stroke. Differentiating between the two conditions is central to patient care as thrombolytic therapy can be helpful in stroke, but detrimental in AD.
Jan 2013
Skull Base CT: Normative Values for Size and Symmetry of the Facial Nerve Canal, Foramen Ovale, Pterygoid Canal, and Foramen Rotundum.PURPOSE: Contrast-enhanced MRI is the mainstay for detecting pathology in the skull base foramina and nerve canals, through demonstration of abnormal enhancement. When MRI is contraindicated, or unable to differentiate tumor from non-neoplastic pathology, high-resolution skull base CT is indicated to assess for nerve canal or foramen widening, which is currently determined subjectively. The purpose of this study is to provide objective CT criteria that may help distinguish between normal asymmetry and pathologic nerve canal or foramen widening. METHODS: Temporal bone CTs of 50 consecutive adults without facial or trigeminal nerve pathology were retrospectively reviewed. Short axis measurements were obtained in the axial plane for three segments of the facial nerve canal (labyrinthine, tympanic, and mastoid), foramen ovale, pterygoid canal and foramen rotundum on both sides in each subject. Descriptive statistics were obtained, and left-right asymmetry was calculated.
Jan 2013
Targeted Biopsy in the Detection of Prostate Cancer Using an Office Based Magnetic Resonance Ultrasound Fusion Device.PURPOSE: Targeted biopsy of lesions identified on magnetic resonance imaging may enhance the detection of clinically relevant prostate cancers. We evaluated prostate cancer detection rates in 171 consecutive men using magnetic resonance ultrasound fusion prostate biopsy. MATERIALS AND METHODS: Subjects underwent targeted biopsy for active surveillance (106) or persistently increased prostate specific antigen but negative prior conventional biopsy (65). Before biopsy, each man underwent multiparametric magnetic resonance imaging at 3.0 Tesla. Lesions on magnetic resonance imaging were outlined in 3 dimensions and assigned increasing cancer suspicion levels (image grade 1 to 5) by a uroradiologist. A biopsy tracking system was used to fuse the stored magnetic resonance imaging with real-time ultrasound, generating a 3-dimensional prostate model on the fly. Working from the 3-dimensional model, transrectal biopsy of target lesions and 12 systematic biopsies were performed with the patient under local anesthesia in the clinic.
Jan 2013
Disappearance of a Small Intracranial Aneurysm as a Result of Vessel Straightening and In-Stent Stenosis Following Use of an Enterprise Vascular Reconstruction Device.In-stent stenosis after stent-assisted coil embolization is a rare but well-known complication. A 32-year-old woman with an unruptured wide-necked left internal carotid artery (ICA) terminus aneurysm and an ipsilateral very small anterior choroidal artery aneurysm underwent stent-assisted coil embolization for the ICA terminus aneurysm. The 4-month follow-up angiography revealed diffuse in-stent stenosis and disappearance of the untreated anterior choroidal artery aneurysm, retaining the patency of the anterior choroidal artery. To our knowledge, this is the first report to demonstrate the course of in-stent stenosis and disappearance of an untreated small intracranial aneurysm as a result. We report this unique case and discuss the interesting mechanism underlying this phenomenon, and also provide a review of the relevant literature.
