Loss of intratumoral macroscopic fat in renal angiomyolipoma following chemoradiation therapy for pancreatic cancer.

Angiomyolipoma (AML) is the most common benign mesenchymal tumour of the kidney. Classically, AML can readily be diagnosed by identifying the negatively attenuating intratumoral macroscopic fat component on non-enhanced CT scans. However, intratumoral macroscopic fat may not be visible on CT scans, mimicking renal cell carcinoma. We report a case of renal AML with CT scan evidence of macroscopic intratumoral fat that was not readily visible on subsequent CT or MRI, presumably owing to a generalized rapid loss of adipose tissue due to cachexia in a patient with pancreatic adenocarcinoma. Radiologists should be aware that AML may lose its intratumoral fat on follow-up imaging and may simulate renal cell carcinoma.

Intrahepatic cholangiocarcinomas mimicking other lesions.

BACKGROUND: While the typical features of large cholangiocarcinomas have been described extensively and are known to radiologists, atypical cholangiocarcinomas are not as well known and radiologists should be more aware of their features. Due to the increasing numbers of cross-sectional imaging studies performed for various reasons, cholangiocarcinomas may be more frequently detected incidentally when small, before they become symptomatic, and might be mistaken for other liver lesions. We studied the appearance of misdiagnosed cholangiocarcinomas. MATERIALS AND METHODS: This is a HIPAA-compliant, IRB-approved retrospective study. Our institutional database and teaching files were searched for cases of cholangiocarcinomas diagnosed between 2004 and 2014 that were initially misdiagnosed or considered indeterminate lesions on MRI or CT. Clinical data and radiological findings were collected. History of malignancy and risk factors for cholangiocarcinoma were recorded. The initial reported diagnosis and time to the correct diagnosis were noted, and the lesions were evaluated for size, enhancement, T1/T2 signal, diffusion restriction, ADC value, capsular retraction, biliary dilatation and the presence of satellite nodules. RESULTS: Nine examples of cholangiocarcinoma that met our inclusion criteria were identified: seven men and two women. All were small, with a mean size of 2.2 cm upon initial diagnosis. All showed a hypervascular pattern of enhancement without washout. Imaging features that are described in the literature as typical for cholangiocarcinomas, such as capsular retraction, satellite nodules, and peripheral biliary dilatation, were not seen. CONCLUSION: Cholangiocarcinomas can be misdiagnosed when they are small and hypervascular. This atypical hypervascular appearance is rare, and may mimic benign liver lesions and other malignant lesions, especially when small. Awareness of the confounding imaging features of these tumors should lead to a more meticulous evaluation of small hypervascular lesions, and may minimize the risk of misdiagnosing early-stage cholangiocarcinomas.

Magnetic resonance elastography and acoustic radiation force impulse for staging hepatic fibrosis: a meta-analysis.

PURPOSE: Elastography is a non-invasive method to quantify fibrosis based on tissue mechanical properties. We performed a meta-analysis to assess the diagnostic accuracy of two such techniques: Acoustic Radiation Force Impulse Imaging (ARFI) or Magnetic Resonance Elastography (MRE) for staging hepatic fibrosis. MATERIALS AND METHODS: Literature databases were searched until June 2013. Inclusion criteria were evaluation of MRE or ARFI, liver biopsy, and reported sensitivity and specificity. A random effects model was used to combine sensitivity and specificity, from which positive (LR+) and negative (LR-) likelihood ratios, diagnostic odds ratios, and area under receiver operating characteristics curve (AUROC) were derived. Differences between MRE and ARFI were compared with t tests (P < 0.05 considered significant). RESULTS: Eleven MRE studies including 982 patients and fifteen ARFI studies including 2,128 patients were selected. AUROC for MRE staging fibrosis were 0.94, 0.97, 0.96, and 0.97 for F1-F4, respectively, whereas AUROC for ARFI staging were 0.82, 0.85, 0.94, and 0.94 for F1-F4, respectively. Significance was found in AUROC between MRE and ARFI for the diagnosis of stage 1 and 2 fibrosis. CONCLUSION: MRE is more accurate than ARFI with a higher combination of sensitivity, specificity, LR, and AUROC particularly in diagnosing early stages of hepatic fibrosis.

Utilization of a clinical prediction rule for abdominal-pelvic CT scans in patients with blunt abdominal trauma.

This study aims to determine if a clinical prediction (CP) rule to identify patients at low risk for intra-abdominal injury (IAI) is being utilized in patients undergoing abdominal computed tomography (CT) following blunt abdominal trauma. A retrospective review of adult patients with blunt abdominal trauma undergoing abdominal CT scans was performed. The CP rule was positive if any of the following were present: systolic blood pressure <90 mmHg; urinalysis >25 red blood cells/high power field; Glasgow Coma Scale score <14; abdominal tenderness; costal margin tenderness; femur fracture; hematocrit <30 %; or pneumothorax or rib fracture on chest X-ray. The CP rule was negative if all variables were negative. Acute intervention was defined as therapeutic laparotomy or angiographic embolization. All variables in the CP rule were obtained in 218/262 (83 %; 95 % confidence interval (CI), 78, 88 %) patients. Of the 44 patients without complete CP rule assessment, 1 (2.3 %; 95 % CI, 0.1 %, 12.0 %) had an IAI but did not undergo therapeutic intervention. IAI was present in 11 (6.7 %; 95 % CI, 3.4, 11.6 %) of the 165 patients with at least one CP rule positive and 4 (36 %; 95 % CI, 11, 69 %) underwent therapeutic intervention. In the CP rule-negative patients, IAI was identified in 1/53 (1.9 %; 95 % CI, 0, 10.1 %) and no therapeutic intervention was required. An important percentage of patients undergoing abdominal CT are not assessed for or have a negative CP rule. Improved implementation of this CP rule may reduce unnecessary abdominal CT scans in patients presenting with blunt abdominal trauma.

Comparison of the sensitivity of a pre-MRI questionnaire and point of care eGFR testing for detection of impaired renal function.

RATIONALE AND OBJECTIVES: The Food and Drug Administration recommends renal function estimation using laboratory testing for patients at risk for chronically reduced kidney function before the administration of gadolinium-based contrast agents (GBCAs). Point-of-care (POC) estimated glomerular filtration rate (eGFR) testing was added to the pre-magnetic resonance (MR) questionnaire at our institution in June 2008 for all patients undergoing a contrast-enhanced MR exam. This study was done to evaluate the effectiveness of a pre-MR screening questionnaire about kidney disease and to assess POC eGFR detection of additional patients at risk for nephrogenic systemic fibrosis. MATERIALS AND METHODS: This retrospective study was approved by our institutional review board and determined to be Health Insurance Portability and Accountability Act compliant. Medical records, laboratory data, and pre-MR questionnaires of all patients who presented for contrast-enhanced MR scans during October 2008 were reviewed. The National Kidney Disease Education Program isotope-dilution mass spectrometry-traceable Modification of Diet in Renal Disease equation was used to calculate eGFRs using the POC creatinine laboratory value, age, race, and gender. Sensitivity and specificity were calculated using 2 × 2 tables, and 95% confidence intervals were calculated with exact binomial confidence intervals. RESULTS: A total of 1167 individuals presented for contrast-enhanced MR scans. Of 13 individuals on dialysis, 2 did not report renal disease. Of 1154 individuals not on dialysis, 25 had an eGFR <30 mL/min/1.73 m(2) (95% CI 1.41%-3.18%). Of these 25, 13 did and 12 did not report renal disease. The sensitivity of the questionnaire for identifying patients with an eGFR <30 mL/min/1.73 m(2) was 63.2%. POC eGFR estimations identified a prevalence of 2.17% (95% CI: 1.41%-3.18%) of the total individuals not on dialysis, with an eGFR <30 mL/min/1.73 m(2). Patients who denied kidney dysfunction had a 1.08% (95% CI: 0.56%-1.88%) posttest probability of having an eGFR <30 mL/min/1.73 m(2). CONCLUSIONS: POC eGFR testing identified a significant number of individuals with renal dysfunction not found by the pre-MR imaging questionnaire alone.

Quantification of adverse events associated with functional MRI scanning and with real-time fMRI-based training.

BACKGROUND: Although functional magnetic resonance imaging (fMRI) is in widespread research use, the safety of this approach has not been extensively quantitatively evaluated. Real-time fMRI (rtfMRI)-based training paradigms use fMRI neurofeedback and cognitive strategies to alter regional brain activation, and are currently being evaluated as a novel approach to treat neurological and psychiatric conditions. PURPOSE: The purpose of this study is to determine the incidence and severity of any adverse events that might be caused by changes in brain activation brought about through fMRI or through rtfMRI-based training paradigms. METHOD: Quantitative adverse event self-report data were obtained from 641 functional imaging scans in 114 chronic pain patients participating in a research clinical trial examining repeated fMRI scans and rtfMRI-based training. Participants recorded potential adverse events during non-scanning baseline, fMRI scanning, or rtfMRI-based training sessions. RESULTS: There were no significant increases in the number of reported adverse events following fMRI or rtfMRI scanning sessions compared to baseline non-scanning sessions in a chronic pain trial (N = 88). There were no reported adverse events of any kind for over 90% of sessions during the course of rtfMRI-based training. When adverse events were reported, they were almost exclusively mild or moderate in severity and similar to those observed in a non-scanning baseline session. There was no increase in adverse events reported by participants receiving feedback from any of four brain regions during repeated rtfMRI-based training scans compared to non-scanning baseline sessions. For chronic pain patients completing the rtfMRI-based training paradigm including up to a total of nine scan sessions (N = 69), neither the number nor severity of reported events increased during the fMRI or rtfMRI scanning portions of the paradigm. There were no significant increases in the number of reported adverse events in participants who withdrew from the study. CONCLUSION: Repeated fMRI scanning and rtfMRI training, consisting of repeated fMRI scanning in conjunction with cognitive strategies and real-time feedback from several regions of interest in multiple brain systems to control brain region activation, were not associated with an increase in adverse event number or severity. These results demonstrate the safety of repetitive fMRI scanning paradigms similar to those in use in many laboratories worldwide, as well as the safety rtfMRI-based training paradigms.

Fronto-striatal dysfunction and potential compensatory mechanisms in male adolescents with fragile X syndrome.

Response inhibition is an important facet of executive function. Fragile X syndrome (FraX), with a known genetic etiology (fragile X mental retardation-1 (FMR1) mutation) and deficits in response inhibition, may be an ideal condition for elucidating interactions among gene-brain-behavior relationships. Functional magnetic resonance imaging (fMRI) studies have shown evidence of aberrant neural activity when individuals with FraX perform executive function tasks, though the specific nature of this altered activity or possible compensatory processes has yet to be elucidated. To address this question, we examined brain activation patterns using fMRI during a go/nogo task in adolescent males with FraX and in controls. The critical comparison was made between FraX individuals and age, gender, and intelligent quotient (IQ)-matched developmentally delayed controls; in addition to a control group of age and gender-matched typically developing individuals. The FraX group showed reduced activation in the right ventrolateral prefrontal cortex (VLPFC) and right caudate head, and increased contralateral (left) VLPFC activation compared with both control groups. Individuals with FraX, but not controls, showed a significant positive correlation between task performance and activation in the left VLPFC. This potential compensatory activation was predicted by the interaction between FMR1 protein (FMRP) levels and right striatal dysfunction. These results suggest that right fronto-striatal dysfunction is likely an identifiable neuro-phenotypic feature of FraX and that activation of the left VLPFC during successful response inhibition may reflect compensatory processes. We further show that these putative compensatory processes can be predicted by a complex interaction between genetic risk and neural function.