Fusion of high B-value diffusion-weighted and T2-weighted MR images increases sensitivity for identification of extraprostatic disease in prostate cancer.

PURPOSE: To evaluate whether fusion of high b-value diffusion-weighted imaging (DWI) and T2-weighted imaging (T2WI) increases radiologists' ability to detect pathologic features responsible for upstaging in prostate cancer patients prior to radical prostatectomy (RP). BASIC PROCEDURES: This was a retrospective study including 103 patients who underwent RP and a prostate MRI performed at 3T. High b-value DWI and T2WI were fused and interpreted by three radiologists with different degrees of experience. Prior to and after fusion, readers answered questionnaires about cancer presence, extraprostatic extension (EPE), seminal vesicle (SV) invasion, lymph node (LN) involvement, and reader confidence. Pathology reports served as the reference standard. MAIN FINDINGS: High b-value DWI-T2WI fusion increased sensitivity for detection of EPE from 65.6% to 77.4% (p < 0.05), SV invasion from 40.5% to 48.8% (p < 0.05), and LN metastasis by 23.8% to 44.4% (p < 0.05). Readers' confidence significantly improved with the use of fusion imaging. Across all readers, confidence of cancer detection increased by 12.5% (p < 0.05), EPE by 14.7% (p < 0.05), SV invasion by 8.1% (p < 0.05), and LN metastasis by 2.5% (p < 0.05) using Wilcoxon signed rank test. PRINCIPAL CONCLUSIONS: Fusion overlay of high b-value DWI and T2WI increases sensitivity for detection of extraprostatic disease resulting in upstaging at the time of RP.

Acute Pancreatitis: How Can MR Imaging Help.

MR imaging is useful for diagnosing acute pancreatitis when the clinical situation is unclear, for elucidating the underlying cause of acute pancreatitis, for evaluating complications and disease severity, and for guiding intervention. MR imaging allows for noninvasive evaluation of the pancreatic parenchyma, biliary and pancreatic ducts, exocrine function, peripancreatic soft tissues, and vascular structures in a single examination. MR imaging is emerging as the imaging examination of choice in acute pancreatitis. In this article, the role of imaging in acute pancreatitis is reviewed with an emphasis on the advantages of MR imaging.