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Purpose: To evaluate the utility of dynamic, contrast-enhanced magnetic resonance imaging (MRI) in combination with single-shot T2-weighted (ssT2) sequences in the differentiation of lipid-poor adrenal adenomas from non-adenomas., Materials and Methods: This retrospective study was approved by the institutional review board and is HIPAA compliant. Between January 2007 and December 2010, 46 patients with MRI demonstrating a lipid-poor adrenal lesion who underwent either surgical resection or a minimum of 24 months of imaging follow-up were identified retrospectively. All images were retrospectively reviewed in blinded fashion by two radiologists. Each adrenal lesion was categorized by dynamic enhancement features and qualitative signal on ssT2 images and was categorized as an adenoma if it demonstrated homogenous enhancement in the arterial phase, washout with capsule enhancement in the delayed phase, and T2 signal isointense to normal adrenal tissue. Any lesion that did not fulfill all the criteria was classified as a non-adenoma. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for characterization of adenoma were calculated for each reader with 95% confidence intervals. A κ test assessed level of agreement between readers., Results: Application of our criteria lead to an MRI diagnosis of lipid-poor adrenal adenoma with a sensitivity of 84.2-89.5% (16/19-17/19), specificity of 96.3% (26/27), positive predictive value of 94.1-94.4% (16/17-17/18), negative predictive value of 89.7-92.9% (26/29-26/28), and accuracy of 91.3-93.5% (42/46-43/46). Agreement between the two readers showed substantial κ agreement for the differentiation of adenoma from non-adenoma., Conclusions: Dynamic, contrast-enhanced T1-weighted three-dimensional gradient echo sequences in combination with ssT2 images can accurately differentiate lipid-poor adrenal adenomas from non-adenomas., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Background: Cholelithiasis affects an estimated 20 million people in the United States yearly; 20% of symptomatic patients will develop acute cholecystitis (AC). A recent single-center study estimating test characteristics of point-of-care ultrasonography (POCUS) for the detection of AC, as defined by gallstones plus sonographic Murphy's or pericholecystic fluid or gallbladder wall-thickening, resulted in a sensitivity and specificity of 87% (95% confidence interval [CI] 66-97) and 82% (95% CI 74-88), respectively. No prior studies have been conducted to estimate the test characteristics of POCUS for the purpose of excluding acute calculous cholecystitis., Objective: To determine whether the finding of gallstones alone on POCUS has high sensitivity, high negative predictive value, and low negative likelihood ratio for the exclusion of AC., Methods: We conducted an analysis using data from a prospective cross-sectional single-center study of POCUS test to estimate the test characteristics using a simplified definition of a positive test - the presence of gallstones alone. Clinical follow-up and pathology reports were used as the reference standard. Test characteristics were calculated and compared to the standard definition, gallstones plus one secondary finding., Results: The overall prevalence of AC was 14% (23 pathology-confirmed cases of 164 included patients). The sensitivity of the simplified definition was 100% (95% CI 85.7-100), negative predictive value 100% (95% CI 92.2-100), and negative likelihood ratio was < 0.1, compared to a sensitivity of 87% (95% CI 66-97%), negative predictive value 97% (95% CI 93-99%), and negative likelihood ratio of 0.16 (95% CI 0.06-0.5)., Conclusion: Simplifying the definition of the test findings on POCUS to gallstones alone has excellent sensitivity and negative predictive value for the exclusion of AC. This finding, if broadly validated prospectively, confirms the practice of excluding acute calculous cholecystitis using POCUS in emergency department patients., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Context: Knowledge of the role that qualitative as opposed to energy aspects of diet play in the accumulation of visceral abdominal adipose tissue (VAT) and subcutaneous abdominal adipose tissue (SAAT) is limited and not conclusive., Objective: A systematic review was conducted to evaluate and summarize the existing literature investigating the relationships between qualitative aspects of diet, from single dietary components to overall dietary patterns, and VAT and SAAT., Data Sources: The PubMed, Web of Science, Embase, and Cochrane databases were searched., Study Selection: Observational and controlled intervention studies that assessed healthy adults or adolescents using magnetic resonance imaging, computed tomography, dual-energy X-ray absorptiometry, or ultrasound were eligible for inclusion. After quality assessment of all eligible studies, 20 observational and 23 controlled intervention studies were included., Data Synthesis: Considering study quality, including nutritional and abdominal adipose tissue assessment, about 30 caloric and noncaloric qualitative aspects of diet were found "to be associated with or affect" VAT and/or SAAT, most notably, medium-chain triacylglycerols, dietary fiber, calcium, phytochemicals, and dietary patterns; for fructose and alcohol, the relationships were less clear., Conclusion: Additional well-designed prospective studies are warranted to confirm current findings and to identify further qualitative aspects of diet that may influence VAT and SAAT accumulation., (© The Author(s) 2015. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Background & Aims: Chronic pancreatitis is characterized by inflammation, atrophy, fibrosis with progressive ductal changes, and functional changes that include variable exocrine and endocrine insufficiency and multiple patterns of pain. We investigated whether abdominal imaging features accurately predict patterns of pain., Methods: We collected data from participants in the North American Pancreatitis Study 2 Continuation and Validation, a prospective multicenter study of patients with chronic pancreatitis performed at 13 expert centers in the United States from July 2008 through March 2012. Chronic pancreatitis was defined based on the detection of characteristic changes by cross-sectional abdominal imaging, endoscopic retrograde cholangiopancreatography, endoscopic ultrasonography, or histology analyses. Patients were asked by a physician or trained clinical research coordinator if they had any abdominal pain during the year before enrollment, those who responded "yes" were asked to select from a list of 5 pain patterns. By using these patterns, we classified patients' pain based on timing and severity. Abnormal pancreatitis-associated features on abdominal imaging were recorded using standardized case report forms., Results: Data were collected from 518 patients (mean age, 52 ± 14.6 y; 55% male; and 87.6% white). The most common physician-identified etiologies were alcohol (45.8%) and idiopathic (24.3%); 15.6% of patients reported no abdominal pain in the year before enrollment. The most common individual pain pattern was described as constant mild pain with episodes of severe pain and was reported in 45% of patients. The most common imaging findings included pancreatic ductal dilatation (68%), atrophy (57%), and calcifications (55%). Imaging findings were categorized as obstructive for 20% and as inflammatory for 25% of cases. The distribution of individual imaging findings was similar among patients with different patterns of pain. The distribution of pain patterns did not differ among clinically relevant groups of imaging findings., Conclusions: Mechanisms that determine patterns and severity of pain in patients with chronic pancreatitis are largely independent of structural variants observed by abdominal imaging techniques. Pancreas-relevant quantitative and qualitative pain measures should be included in the evaluation of patients with chronic pancreatitis to assess pain severity independently of imaging findings., (Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of our study was to find out how much energy is applicable in second-generation dual source high-pitch computed tomography (CT) in imaging of the abdomen., Materials and Methods: We examined an upper abdominal phantom using a Somatom Definition Flash CT-Scanner (Siemens, Forchheim, Germany). The study protocol consisted of a scan-series at 100 kV and 120 kV. In each scan series we started with a pitch of 3.2 and reduced it in steps of 0.2, until a pitch of 1.6 was reached. The current was adjusted to the maximum the scanner could achieve. Energy values, image noise, image quality, and radiation exposure were evaluated., Results: For a pitch of 3.2 the maximum applicable current was 142 mAs at 120 kV and in 100 kV the maximum applicable current was 114 mAs. For conventional abdominal imaging, current levels of 200 to 260 mAs are generally used. To achieve similar current levels, we had to decrease the pitch to 1.8 at 100 kV - at this pitch we could perform our imaging at 204 mAs. At a pitch of 2.2 in 120 kV we could apply a current of 206 mAs., Conclusion: We conclude our study by stating that if there is a need for a higher current, we have to reduce the pitch. In a high-pitch dual source CT, we always have to remember where our main focus is, so we can adjust the pitch to the energy we need in the area of the body that has to be imaged, to find answers to the clinical question being raised.

Background & Aims: Magnetic resonance imaging (MRI) is used to assess the outcome of infliximab (IFX) therapy in patients with perianal fistulizing Crohn''s disease (pfCD). However, few long-term data are available about its efficacy. Methods: We assessed 59 patients with pfCD by MRI and clinical evaluation at baseline. Treated patients then received paired clinical and MRI examinations for a median time period of 36 (11–53.3) weeks. Short-, mid-, and long-term effects of therapy, as well as the ability of MRI to predict treatment outcome and need for surgery, were evaluated. Results: Compared with the baseline MRI, the short-term follow-up MRI (n = 29) revealed a reduced number of fistula tracks in 13.8% and in the inflammatory activity in 55.2% of patients, respectively; mid-term MRI (n = 25) in 56% and in 52%, respectively; and long-term MRI (n = 13) in 15.4% and in 31%, respectively. Improvement of pfCD based on MRI results coincided with clinical improvement in 54.7% of the patients. Short-term and mid-term (but not long-term) MRI showed a significant decrease in the activity score. Therapy outcome was worse among patients with persisting fistulas (P = .01), collections (P = .009), and rectal wall involvement (P = .01) in the final MRI. Patients with single-branched fistulas (P < .0001) and collections (P = .006) in their baseline MRI were more likely to undergo surgery. Conclusions: MRI is a useful technique for evaluation of pfCD during the first year of follow-up. In the long-term, the MRI improvement coincides with clinical and endoscopic response to IFX in 50% of the patients. [Copyright &y& Elsevier]

Objectives: to compare vascular and parenchymal enhancement in abdominal computed tomography (CT) using two iodine concentrations (370 vs 300mgI/mL) of the same contrast medium (CM) molecule (iopromide), using fixed iodine delivery rate (IDR, 1.2gI/s) and total iodine load (630mgI/kg)., Methods: 144 patients were randomized into two groups: group A receiving iopromide 370 and group B receiving iopromide 300. Attenuation values (AV) were measured in correspondence to key anatomical structures on different phases and compared between groups with parametrical tests. Qualitative analysis was also performed. Peak injection pressure and local discomfort at the site of injection (pain and warmth) were registered., Results: mean AV of abdominal aorta in late arterial phase were 300.32±59.76 for group A and 298.2±59.14 for group B (p=0.8); mean AV of portal vein in portal phase were 190.5±29.92 for group A and 192.91±24.12 for group B (p=0.6). Mean AV of liver parenchyma in portal phase were 124.73±18.22 for group A and 125.11±15.7 for group B (p=0.9); mean AV of liver at equilibrium were 85.11±7.75 for group A and 85.41±8.09 for group B (p=0.8). Qualitative analysis did not show significant differences between groups (p>0.05). Median peak injection pressure was lower in group B (93psi, 76-172) than in group A (115psi, 88-288, p<0.0001), while discomfort at injection site was not significantly different (p>0.05)., Conclusions: with fixed IDR and total iodine load, comparable quantitative and qualitative enhancement can be achieved with different concentrations of the same CM. Peak injection pressure increases using CM with higher iodine concentration., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Laboratory mice develop naturally occurring lesions that affect biomedical research. Hydronephrosis is a recognized pathologic abnormality of the mouse kidney. Acquired hydronephrosis can affect any mouse, as it is caused by any naturally occurring disease that impairs free urine flow. Many etiologies leading to this condition are of particular significance to aging mice. Non-invasive ultrasound imaging detects renal pelvic dilation, renal enlargement, and parenchymal loss for pre-mortem identification of this condition. High-frequency ultrasound transducers produce high-resolution images of small structures, ideal for detecting organ pathology in mice. Using a 40 MHz linear array transducer, we obtained high-resolution images of a diversity of pathologic lesions occurring within the abdomen of seven geriatric mice with acquired hydronephrosis that enabled a determination of the underlying etiology. Etiologies diagnosed from the imaging results include pyelonephritis, neoplasia, urolithiasis, mouse urologic syndrome, and spontaneous hydronephrosis, and were confirmed at necropsy. A retrospective review of abdominal scans from an additional 149 aging mice shows that the most common etiologies associated with acquired hydronephrosis are mouse urologic syndrome and abdominal neoplasia. This report highlights the utility of high-frequency ultrasound for surveying research mice for age-related pathology, and is the first comprehensive report of multiple cases of acquired hydronephrosis in mice.

Purpose: To study liver imaging with volume acceleration-flexible (LAVA-Flex) for abdominal magnetic resonance imaging (MRI) at 3.0 T and compare the image quality of abdominal organs between LAVA-Flex and fast spoiled gradient-recalled (FSPGR) T1-weighted imaging., Materials and Methods: Our Institutional Review Board approval was obtained in this retrospective study. Sixty-nine subjects had both FSPGR and LAVA-Flex sequences. Two radiologists independently scored the acquisitions for image quality, fat suppression quality, and artifacts and the values obtained were compared with the Wilcoxon signed rank test. According to the signal intensity (SI) measurements, the uniformity of fat suppression, the contrast between muscle and fat and normal liver and liver lesions were compared by the paired t-test. The liver and spleen SI on the fat-only phase were analyzed in the fatty liver patients., Results: Compared with FSPGR imaging, LAVA-Flex images had better and more homogenous fat suppression and lower susceptibility artifact (qualitative scores: 4.70 vs. 4.00, 4.86% vs. 7.14%, 4.60 and 4.10, respectively). The contrast between muscle and fat and between the liver and pathologic lesions was significantly improved on the LAVA-Flex sequence. The contrast value of the fatty liver and spleen was higher than that of the liver and spleen., Conclusion: The LAVA-Flex sequence offers superior and more homogenous fat suppression of the abdomen than does the FSPGR sequence. The fat-only phase can be a simple and effective method of assessing fatty liver., (© 2013 Wiley Periodicals, Inc.)

Aim: To describe the imaging features of solitary fibrous tumors (SFTs) in the abdomen and pelvis, and the clinical and pathologic correlations., Methods: Fifteen patients with pathologically confirmed SFTs in the abdomen and pelvis were retrospectively studied with imaging techniques by two radiologists in consensus. Patients underwent unenhanced and contrast-enhanced imaging, as follows: 3 with computed tomography (CT) and magnetic resonance imaging (MRI) examination, 8 with CT examination only, and 4 with MRI examination only. Image characteristics such as size, shape, margin, attenuation or intensity, and pattern of enhancement were analyzed and correlated with the microscopic findings identified from surgical specimens. In addition, patient demographics, presentation, and outcomes were recorded., Results: Of the 15 patients evaluated, local symptoms related to the mass were found in 11 cases at admission. The size of the mass ranged from 3.4 to 25.1 cm (mean, 11.5 cm). Nine cases were round or oval, 6 were lobulated, and 10 displaced adjacent organs. Unenhanced CT revealed a heterogeneous isodense mass in 7 cases, homogeneous isodense mass in 3 cases, and punctuated calcification in one case. On MRI, most of the lesions (6/7) were heterogeneous isointense and heterogeneous hyperintense on T1-weighted images and T2-weighted images, respectively. All tumors showed moderate to marked enhancement. Heterogeneous enhancement was revealed in 11 lesions, and 7 of these had cysts, necrosis, or hemorrhage. Early nonuniform enhancement with a radial area that proved to be a fibrous component was observed in 4 lesions, which showed progressive enhancement in the venous and delayed phase. No statistical difference in the imaging findings was observed between the histologically benign and malignant lesions. Three patients had local recurrence or metastasis at follow-up., Conclusion: Abdominal and pelvic SFTs commonly appeared as large, solid, well-defined, hypervascular masses with variable degrees of necrosis or cystic change that often displaced adjacent structures.

Purpose: Breath-holding is an established strategy for reducing motion artifacts in abdominal imaging. However, the breath-holding capabilities of patients are often overstrained by scans with large coverage and high resolution. In this work, a new strategy for coping with resulting incomplete breath-holds in abdominal imaging is suggested., Methods: A sampling pattern is designed to support image reconstruction from undersampled data acquired up to any point in time using compressed sensing and parallel imaging. In combination with a navigator-based detection of the onset of respiration, it allows scan termination and thus reconstruction only from consistent data, which suppresses motion artifacts. The spatial resolution is restricted by a lower bound of the sampling density and is increased over the scan, to strike a compromise with the signal-to-noise ratio and undersampling artifacts for any breath-hold duration., Results: The sampling pattern is optimized in phantom experiments and is successfully applied in abdominal gradient-echo imaging including water-fat separation on volunteers., Conclusions: The new strategy provides images in which motion artifacts are minimized independent of the breath-holding capabilities of patients, and which enhance in terms of spatial resolution, signal-to-noise ratio, and undersampling artifacts with the a priori unknown breath-hold duration actually achieved in a particular scan., (Copyright © 2013 Wiley Periodicals, Inc.)

Aim: To retrospectively and prospectively compare diffusion-weighted (DW) images in the abdomen in a 1.5T system and 3.0T systems with and without two-channel functionality for B1 shimming., Methods: DW images of the abdomen were obtained on 1.5T and 3.0T (with and without two-channel functionality for B1 shimming) scanners on 150 patients (retrospective study population) and 10 volunteers (prospective study population). Eight regions were selected for clinical significance or artifact susceptibility (at higher field strengths). Objective grading quantified signal-to-noise ratio (SNR), and subjective evaluation qualified image quality, ghosting artifacts, and diagnostic value. Statistical significance was calculated using χ(2) tests (categorical variables) and independent two-sided t tests or Mann-Whitney U tests (continuous variables)., Results: The 3.0T using dual-source parallel transmit (dpTX 3.0T) provided the significantly highest SNRs in nearly all regions. In regions susceptible to artifacts at higher field strengths (left lobe of liver, head of pancreas), the SNR was better or similar to the 1.5T system. Subjectively, both dpTX 3.0T and 1.5T systems provided higher image quality, diagnostic value, and less ghosting artifact (P < 0.01, most values) compared to the 3.0T system without dual-source parallel transmit (non-dpTX 3.0T)., Conclusion: The dpTX 3.0T scanner provided the highest SNR. Its image quality, lack of ghosting, and diagnostic value were equal to or outperformed most currently used systems.

Aggressive angiomyxoma is a rare soft-tissue tumor which usually occurs in female patients of reproductive age. Its occurrence in men is even more unusual and as illustrated in this case the difference between pathology suggested by a physical examination and its actual extent can be quite striking. We present a case report of an 81-year-old man with the typical MRI appearances of a pelvic aggressive angiomyxoma, describe imaging and histopathologic features of this rarely seen locally infiltrative neoplasm and also discuss therapeutic options for patients with an aggressive angiomyxoma.