Limited utility of MRA for acute bowel ischemia after portal venous phase CT.

PURPOSE: Mesenteric ischemia and ischemic colitis are uncommon but potentially life-threatening causes of acute abdominal pain. Portal venous phase computed tomography (CT) is routinely ordered in the emergency room setting for abdominal pain, but subsequent MR angiography may be requested for additional evaluation of the mesenteric vasculature. We compare the concordance of CT and magnetic resonance angiography (MRA) for acute bowel ischemia. MATERIALS AND METHODS: Thirty-two patients who underwent contrast-enhanced MRA for bowel ischemia after having undergone CT evaluation within the preceding 2 weeks were identified. A retrospective review of imaging, treatment history, surgical, and pathology reports was conducted. Two radiologists each reviewed the imaging studies in a blinded fashion. RESULTS: Ten cases of bowel ischemia were confirmed by endoscopy and/or surgical pathology. CT correctly identified bowel findings in all cases. Intraobserver agreement between CT and MRA for all vessels was 0.68 and 0.63, highest for the superior mesenteric artery. Interobserver agreement was 0.74 for MRA and 0.78 for CT. Vascular findings were only directly mentioned in 10 of 32 CT reports (and 7 of 10 cases with confirmed bowel ischemia). MRA only detected two additional or alternative diagnoses. CONCLUSION: Portal venous phase CT and MRA demonstrate a high degree of concordance for vascular evaluation. Reviewed CT examinations were sufficient to assess the patency of the mesenteric vasculature, but vascular findings were not reported in most cases. A direct description within the report may have obviated the request for further MR imaging. MRA adds little value after portal venous CT in assessing bowel ischemia.

Imaging of tailgut cysts.

Tailgut cysts are congenital lesions that arise from the primitive hindgut in the true embryonic tail but fail to regress during gestation. These lesions are rare and more frequently encountered later in life and more commonly in women, and are the most common primary retrorectal tumor. Tailgut cysts may be asymptomatic or cause rectal bleeding, pain, or symptoms related to mass effect on the rectum or bladder. Pathologically, tailgut cysts are typically multilocular, lined with a variety of epithelial cell types, and are most frequently benign. Imaging is the linchpin of diagnosis due risks associated with biopsy. The purpose of this pictorial review is to present the spectrum of imaging findings associated with tailgut cysts on CT and MRI with focus on the use of advanced MRI and diffusion-weighted imaging. We present case examples of tailgut cysts, their CT and MR imaging findings, and diagnostic and management considerations.

Prostate magnetic resonance imaging: challenges of implementation.

Prostate cancer is among the most common causes of cancer and cancer deaths in men. Screening methods and optimal treatments have become controversial in recent years. Prostate magnetic resonance imaging (MRI) is gaining popularity as a tool to assist diagnosis, risk assessment, and staging. However, implementation into clinical practice can be difficult, with many challenges associated with image acquisition, postprocessing, interpretation, reporting, and radiologic-pathologic correlation. Although state-of-the-art technology is available at select sites for targeting tissue biopsy and interpreting multiparametric prostate MRI, many institutions struggle with adapting this new technology into an efficient multidisciplinary model of patient care. This article reviews several of the challenges that radiologists should be aware of when integrating prostate MRI into their clinical practice.