Faculty Bibliography

This article provides an updated review on the imaging evaluation of cystic renal masses with focus on the Bosniak classification system, discusses current imaging techniques for evaluating these lesions, reviews benign and malignant etiologies of cystic renal masses, describes pitfalls in the evaluation of these lesions, and discusses current and future directions in the management of cystic renal masses.

Perforated duodenal ulcer following RYGB is an unusual clinical situation that may be a diagnostic challenge. Only 23 cases have previously been reported. We present five cases. The hallmark of visceral perforation, namely pneumoperitoneum, was not seen in three of the four cases that underwent cross sectional imaging. This is perhaps due to the altered anatomy of the RYGB that excludes air from the duodenum. Our cases had more free fluid than expected. The bariatric surgeon should not wait for free intraperitoneal air to suspect duodenal perforation after RYGB.

The ACR Incidental Findings Committee (IFC) presents recommendations for renal masses that are incidentally detected on CT. These recommendations represent an update from the renal component of the JACR 2010 white paper on managing incidental findings in the adrenal glands, kidneys, liver, and pancreas. The Renal Subcommittee, consisting of six abdominal radiologists and one urologist, developed this algorithm. The recommendations draw from published evidence and expert opinion and were finalized by informal iterative consensus. Each flowchart within the algorithm describes imaging features that identify when there is a need for additional imaging, surveillance, or referral for management. Our goal is to improve quality of care by providing guidance for managing incidentally detected renal masses.

Because liver fibrosis can be treated, it is important to diagnose liver fibrosis noninvasively and monitor response to treatment. Although ultrasound (grayscale and Doppler) can diagnose cirrhosis, it does so unreliably using morphologic and sonographic features and cannot diagnose the earlier, treatable stages of hepatic fibrosis. Transient elastography, ultrasound elastography with acoustic radiation force impulse, and MR elastography are modalities that can assess for hepatic fibrosis. Although all international organizations recommend ultrasound for screening for hepatocellular carcinoma, ultrasound is particularly limited for identifying hepatocellular carcinoma in patients with obesity, nonalcoholic fatty liver disease, and nodular cirrhotic livers. In these patient groups as well as patients who are on the liver transplant wait list, ultrasound is so limited that consideration can be made for screening for hepatocellular carcinoma with either MRI or multiphase CT. Additionally, patients who have been previously diagnosed with and treated for hepatocellular carcinoma require continued surveillance for recurrent hepatocellular carcinoma. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Pancreatic adenocarcinoma is associated with poor overall prognosis. Complete surgical resection is the only possible option for cure. As such, increasingly complex surgical techniques including sophisticated vascular reconstruction are being used. Continued advances in surgical techniques, in conjunction with use of combination systemic therapies, and radiation therapy have been suggested to improve outcomes. A key aspect to surgical success is reporting of pivotal findings beyond absence of distant metastases, such as tumor size, location, and degree of tumor involvement of specific vessels associated with potential perineural tumor spread. Multiphase contrast-enhanced multidetector CT and MRI are the imaging modalities of choice for pretreatment staging and presurgical determination of resectability. Imaging modalities such as endoscopic ultrasound and fluorine-18-2-fluoro-2-deoxy-D-glucose imaging with PET/CT are indicated for specific scenarios such as biopsy guidance and confirmation of distant metastases, respectively. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

OBJECTIVE: The objective of our study was to assess the utility of CT features in the diagnosis of cecal volvulus. MATERIALS AND METHODS: Forty-three patients undergoing CT for cecal volvulus and with surgical or clinical follow-up were included. Two radiologists (11 years and 1 year of experience) evaluated CT examinations for the following: whirl sign, abnormal cecal position, "bird beak" sign, severe cecal distention, mesenteric engorgement, a newly described "central appendix" sign (defined as abnormal appendix position near midline), and overall impression for cecal volvulus. Univariable and multivariable assessments were performed. Patients with CT examinations in which the appendix was not visible were excluded from calculations involving the central appendix sign. RESULTS: Fifty-one percent (n = 22) of patients had cecal volvulus. All CT findings were significantly more common in patients with cecal volvulus (p < 0.01) other than mesenteric engorgement for reader 1 (p = 0.332). Readers 1 and 2 identified the central appendix sign in 92.9% and 92.3% of patients with volvulus versus in 37.5 and 31.1% of patients without volvulus. The whirl sign exhibited a sensitivity for cecal volvulus of 90.9% for reader 1 and 95.5% for reader 2, and a specificity of 61.9% for both readers. Abnormal cecal position exhibited a sensitivity of 90.0% for reader 1 and 100.0% for reader 2 and a specificity of 66.7% and 38.1%. The bird beak sign exhibited a sensitivity of 86.4% for reader 1 and 100.0% for reader 2 and a specificity of 85.7% and 71.4%. Severe cecal distention exhibited a sensitivity of 100.0% for both readers and a specificity of 81.0% and 61.9%. Mesenteric engorgement exhibited a sensitivity of 40.9% for reader 1 and 100.0% for reader 2 and a specificity of 76.2% and 71.4%. The central appendix sign exhibited a sensitivity of 92.9% for reader 1 and 92.3% for reader 2 and a specificity of 62.5% and 68.8%. Overall impression exhibited a sensitivity of 100.0% for both readers and a specificity of 76.2% and 57.1%. At multivariable analysis, the AUC for cecal volvulus ranged from 0.787 to 0.931, and the whirl sign was an independent predictor of volvulus for both readers (p