Beyond hepatic hemangiomas: the diverse appearances of gastrointestinal and genitourinary hemangiomas.

Hemangiomas are common lesions, best known for their appearance in the liver. Their appearance in less common locations, such as the gastrointestinal and genitourinary tracts, is less well known. We will review the typical and atypical appearance of hemangiomas in these locations on sonography, CT, and MRI.

Diffusion-weighted MR imaging of solid and cystic lesions of the pancreas.

Diffusion-weighted magnetic resonance (MR) imaging is increasingly used in the detection and characterization of pancreatic lesions. Diffusion-weighted imaging may provide additional information to radiologists evaluating patients who have cystic or solid neoplasms of the pancreas. Because of greater freedom of motion of water molecules in fluid-rich environments, simple cysts in the pancreas have higher signal intensity on diffusion-weighted images with a b value of 0 sec/mm2 and lower signal intensity on high-b-value images. High apparent diffusion coefficient (ADC) values can be obtained on ADC maps because of the T2 "shine-through" effect. In contrast, solid neoplasms of the pancreas show increased signal intensity relative to the pancreas on diffusion-weighted images with a b value of 0 sec/mm2 and relatively high signal intensity on high-b-value images. Diffusion-weighted imaging can help detect solid pancreatic neoplasms with extremely dense cellularity or extracellular fibrosis by demonstrating significantly low ADC values, and these neoplasms may be better detected on diffusion-weighted MR images because of better contrast, although the resolution is generally worse. However, diffusion-weighted imaging may not be capable of helping definitively characterize solid lesions as inflammatory or neoplastic because of an overlap in ADC values between the two types. For example, it is difficult to distinguish poorly differentiated pancreatic adenocarcinoma from mass-forming pancreatitis at diffusion-weighted imaging because of similarly low ADC values attributed to dense fibrosis.

Unexplained renal colic: what is the utility of IV contrast?

PURPOSE: The aim of this study was to evaluate the benefit of intravenous (IV) contrast in patients with suspected renal colic and unremarkable unenhanced MDCT. MATERIALS AND METHODS: One thousand two hundred and four patients with suspected ureterolithiasis were evaluated with unenhanced MDCT. Seven hundred and eight patients that had additional imaging following IV contrast were our study group. RESULTS: Of the patients, 9.4% (67/708) had abnormalities seen only on contrast-enhanced exams. In 53.1% (376/708) of the patients, no additional finding was identified after IV contrast. CONCLUSION: IV contrast in patients with renal colic is rarely helpful.