Objective To reassess the value of CT and clinical criteria as prognostic and severity indicators in acute pancreatitis and to investigate the correlation between them.Methods Of 65 cases of acute pancreatitis,the hospitalization days,fevering days and entire complications (including local and systemic complications)were regarded as clinical endpoints.CT criteria included Balthazar's plain CT scan score,necrosis score,CT severity index(CTSI) and London's PSI score.Clinical criteria included Ranson and APACHE Ⅱscore.Using analysis of variance,t-test and multiple linear regression analysis,the correlation between each criteria and the three clinical endpoints was examined as well as the relation between CT and clinical criteria.The power of each criteria and combination of CT and clinical criteria in predicting entire complications of AP was assessed and compared by using ROC analysis.Results The mean scores of PSI,Ranson and APACHE Ⅱamong three groups classified according to entire complications were significantly different.Except Balthazar's plain CT scan criteria,each criteria's mean scores in group with local complications was signifiantly higher than that in group without and entire complications was significantly more in sever group than that in mild group.Mean hospitalization days and fevering days were significantly longer in sever group than that in mild group with Ranson Score.PSI and Ranson score had linear correlation with fevering days,and Ranson score had linear correlation with hospitalization days.In CT criteria,a linear correlation was only found between PSI and Ranson score.ROC analysis showed the Az of Ranson score was the largest,and there was no increase in the Az when CT criteria were added to clinical criteria.Conclusion The predictive value of Ranson score and PSI are superior to that of others.Clinical criteria is superior in predicting systemic complications,whereas CT is superior in predicting local complications.There is no improvement in predicting entire complications of AP when CT criteria are added to clinical criteria.The findings of plain CT scan is found to be some laggard compared with that of clinic.CT scan and short follow-up are important in the evaluation of AP.