The role of diffusion weighted MR imaging in the diagnosis of acute pancreatitis.
INTRODUCTION Acute pancreatitis runs an unpredictable course. The early prediction of the severity of an acute attack has important implications for management and timely intervention. AIM To assess the prognostic accuracy of Ranson and APACHE II and III scoring systems in predicting the severity of acute pancreatitis. METHODS One hundred fifty-three patients with acute pancreatitis (67.3% gallstone-related, 9.2% alcoholic, 17% idiopathic, and 6.5% of miscellaneous causes) were studied prospectively. Data conforming to the scoring systems were recorded 24 (the APACHE scores) and 48 hours (the Ranson score) after admission. Analysis was performed by using receiver operating characteristic curves (ROC), area under a curve (AUC), and by comparing likelihood ratios of positive test (LRPT). RESULTS One hundred nineteen cases of pancreatitis were classified as mild, and 34 were classified as severe. The mortality rate was 3.2%. All three scores correlated with length of stay and disease severity. AUC for Ranson was found to be significantly larger than AUC for APACHE II and APACHE III score (0.817, cut-off > or =3; 0.618, cut-off, > or =10; and 0,676, cut-off > or =42 respectively). The Ranson score achieved the highest sensitivity and the lowest false-negative rate, but the positive and negative predictive values and LRPT were of similar extent for all three scores. CONCLUSION The APACHE III offers little, if any, advantage over the APACHE II score. Ranson criteria proved to be as powerful a prognostic model as the more complicated APACHE II and III scoring systems, but with the disadvantage of a 24-hour delay.