Abstract: Objective: To investigate the diagnostic value of MRCP combined with conventional MRI in determination of the etiology of gallbladder enlargement.Methods: MRCP,conventional axial T1WI and T2WI sequences were performed in 29 patients with gallbladder enlargement.Imaging findings were analyzed retrospectively.Each pre-operative imaging diagnosis related to the etiology was correlated with findings of direct vision of laparoscopic or surgical operation,and post-operative examination of pathology.Results: 1) Different degree of gallbladder enlargement was showed in each patient of the study,the longitudinal ranges of the gallbladder were from 8.01 cm to 18.13 cm(mean 11.93 cm ± 3.20),the transverse diameters ranged from 4.12 cm to 7.05 cm(mean 4.59 cm ± 0.91).2) Final etiological diagnosis was as follows:18 cases were benign lesions,they included choledocholithiasis in 7 cases,acute and chronic cholecystitis associated with cholecystolithiasis in 4 cases,gallbladder adenomyomatosis in 3 cases,Mirizzi syndrome in 3 cases and atonic gallbladder in 1 case.Diagnostic sensitivity and specificity of MRCP combined with conventional MRI were 83.33%(15/18) and 72.22%(13/18),respectively;11 cases were malignant lesions which included gallbladder cancer in 1 case,hepatic hilar cholangiocarcinoma in 1 case,common bile duct carcinoma in 5 cases and periampullary carcinoma in 4 cases.Diagnostic sensitivity and specificity of MRCP combined with conventional MRI were 90.90%(10/11) and 81.81%(9/11),respectively.Conclusion: Gallbladder enlargement might resulted from benign and malignant lesions in the gallbladder and extrahepatic bile duct,MRCP examination combined with conventional axial T1WI and T2WI were helpful in defining the etiology of diseases.