Chronic pancreatitis: MRCP versus ERCP for quantitative caliber measurement and qualitative evaluation

PURPOSE: To retrospectively compare-in patients with chronic pancreatitis-magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP) for measurement of main pancreatic duct (MPD) diameter by using area intensity measurement (AIM) at MRCP and full width at half maximum (FWHM) at ERCP and to retrospectively determine the accuracy of MRCP for depiction of pathologic changes by using ERCP as the reference standard. MATERIALS AND METHODS: The institutional review board approved this study and waived the need to obtain informed consent. Both MRCP and ERCP were performed in 24 patients with chronic pancreatitis (21 men, three women; mean age, 54 years +/- 14 [standard deviation]). The diameter of the MPD was determined by using both methods at the same sites in the head, body, and tail of the pancreas. MRCP and ERCP measurements involved AIM and FWHM techniques, respectively. For qualitative evaluation, visualization of the MPD and pathologic findings was also examined by using both methods. Paired t and Wilcoxon matched-pair signed rank tests were performed for the quantitative and qualitative evaluations, respectively. RESULTS: The mean diameter of the MPD at ERCP was 1.5 times larger, on average, than that at MRCP; differences were statistically significant for each segment, as well as for the entire duct system. For qualitative evaluation, MRCP tended to be superior to ERCP for delineation of the MPD. Overall sensitivity, specificity, and accuracy values of MRCP for delineating pathologic pancreatic changes were 88% (87 of 99), 98% (44 of 45), and 91% (131 of 144), respectively. CONCLUSION: Use of ERCP tends to result in overestimation of the caliber of the MPD. MRCP can enable accurate evaluation of the condition of the pancreatic duct and its changes in patients with chronic pancreatitis.