Influence of cholecystectomy on the flow dynamic pattern of bile in the extrahepatic bile duct: Assessment by cine-dynamic MRCP with spatially-selective IR pulse.

ABSTRACT

PURPOSE: To evaluate the influence of cholecystectomy on the flow dynamic pattern of bile in the extrahepatic bile duct by using cine-dynamic MRCP with spatially-selective inversion-recovery (IR) pulse non-invasively. MATERIALS AND METHODS: 56 patients with cholecystectomy and 48 control subjects without cholecystectomy who underwent cine-dynamic MRCP with spatially-selective IR pulse at 1.5 T or 3 T (TR/TE, 4000 msec/500 msec; echo train spacing, 6.5 msec; echo train length, 172; section thickness, 50 mm; matrix, 320 × 320; field of view, 320 × 320 mm; bandwidth, 488 Hz; and inversion time, 2200 msec). In cine-dynamic MRCP, IR pulse with 20 mm width was placed on the common bile duct (CBD) to evaluate the movement of bile (antegrade and reversed bile flow). Cine-dynamic MRCP imaging was scanned every 15 s (imaging, 4 s; rest, 11 s) during 5 min to acquire a series of single-shot images (a total of 20 images). The frequency that antegrade or reversed bile flow was observed in the extrahepatic bile duct, and 5-point grading score based on the moving distance of antegrade or reversed bile flow were compared between the groups. Both groups were compared using the χ2 and Mann-Whitney U tests (P < 0.05 considered significant). RESULTS: Antegrade bile flow was observed more frequently in the cholecystectomy group than in the non-cholecystectomy group (5.1 times vs. 2.8 times, P = 0.008). Mean grading score of antegrade bile flow was significantly greater in the cholecystectomy group than in the non-cholecystectomy group (mean grade, 0.33 vs 0.21; P = 0.014). Regarding reversed bile flow, there were no significant differences in the frequency and grading score between cholecystectomy group and non-cholecystectomy group. CONCLUSION: Antegrade bile flow was observed more frequently and predominantly in patients after cholecystectomy in cine-dynamic MRCP with spatially-selective IR pulse while reversed bile flow was observed equivalently.