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Research Publications
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.
