Dynamic MR pancreatography after secretin administration: image quality and diagnostic accuracy.
OBJECTIVE: The objective of our study was to assess the improvement of image quality and diagnostic accuracy of secretin-enhanced MR pancreatography compared with conventional MR pancreatography. SUBJECTS AND METHODS: Ninety-five patients were studied with a 1.5-T scanner using a T2-weighted single-slice fast spin-echo sequence. Image quality and diameter of the head, body, and tail portion of the pancreatic main duct, the accessory duct, and the side branches were assessed before and after IV administration of secretin. Diagnoses before and after secretin administration were evaluated in a blinded fashion and correlated to the final diagnoses based on endoscopic retrograde cholangiopancreatography (ERCP), intraoperative results, and clinical follow-up as the reference standard. RESULTS: In patients with a normal pancreatic duct, the visualization of all portions of the main pancreatic duct and the accessory duct was significantly improved with dynamic MR pancreatography (p< or = 0.001). In patients with chronic pancreatitis, the visualization of the main duct was also significantly improved with dynamic MR pancreatography (p< or = 0.05). However, the visualization of the minor duct and the side branches was significantly improved only in patients showing no ductal stricture (p< or = 0.05), compared with those with ductal stricture (not significant). The overall sensitivity for the detection of chronic pancreatitis increased from 77% to 89% using secretin-enhanced MR pancreatography. A pancreas divisum was found in eight patients before and 13 patients after secretin administration. The overall negative predictive value of MR pancreatography increased from 84% to 98% after secretin administration. CONCLUSION: Improvement in image quality after secretin stimulation increases the diagnostic value of MR pancreatography in patients with a normal or nondilated main pancreatic duct and may obviate invasive procedures such as ERCP.