CT Evaluation of Long-Term Changes in Common Bile Duct Diameter after Cholecystectomy

Abstract

Purpose The present study aimed to investigate the frequency and extent of compensatory common

bile duct (CBD) dilatation after cholecystectomy, assess the time between cholecystectomy and CBD

dilatation, and identify potentially useful CT findings suggestive of obstructive CBD dilatation.

Materials and Methods This retrospective study included 121 patients without biliary obstruction

who underwent multiple CT scans before and after cholecystectomy at a single center between 2009

and 2011. The maximum short-axis diameters of the CBD and intrahepatic duct (IHD) were measured

on each CT scan. In addition, the clinical and CT findings of 11 patients who were initially excluded

from the study because of CBD stones or periampullary tumors were examined to identify distinguishing

features between obstructive and non-obstructive CBD dilatation after cholecystectomy.

Results The mean (standard deviation) short-axis maximum CBD diameter of 121 patients was 5.6

(± 1.9) mm in the axial plane before cholecystectomy but increased to 7.9 (± 2.6) mm after cholecystectomy

(p < 0.001). Of the 106 patients with a pre-cholecystectomy axial CBD diameter of < 8 mm, 39

(36.8%) showed CBD dilatation of ≥ 8 mm after cholecystectomy. Six of the 17 patients with longterm

(> 2 years) serial follow-up CT scans (35.3%) eventually showed a significant (> 1.5-fold) increase

in the axial CBD diameter, all within two years after cholecystectomy. Of the 121 patients without obstruction

or related symptoms, only one patient (0.1%) showed IHD dilatation > 3 mm after cholecystectomy.

In contrast, all 11 patients with CBD obstruction had abdominal pain and abnormal laboratory

indices, and 81.8% (9/11) had significant dilatation of the IHD and CBD.

Conclusion Compensatory non-obstructive CBD dilatation commonly occurs after cholecystectomy

to a similar extent as obstructive dilatation. However, the presence of relevant symptoms, significant

IHD dilatation, or further CBD dilatation 2–3 years after cholecystectomy should raise suspicion of

CBD obstruction.