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Gastrointestinal Imaging

E2215. Mild Asymptomatic Intrahepatic Biliary Dilation After Cholecystectomy, Likely an Incidental Finding

Atkinson C1,  Lisanti C1,2,  Schwope R1,2,  Ramsey D1,  Dinh T.1 1. San Antonio Military Medical Center, Fort Sam Houston, TX ; 2. Uniformed Services University of the Health Sciences, Bethesda, MD

Address correspondence to C. Lisanti (lisantic@aol.com)

Objective: The purpose of this study is to evaluate the prevalence of intra- and extrahepatic ductal dilatation in asymptomatic individuals after cholecystectomy.

Materials and Methods: This institutional review board–approved retrospective cohort study evaluated the prevalence of intra- and extrahepatic biliary dilation in 77 consecutive patients after cholecystectomy who had CT obtained in the portal venous phase. These were then compared to age- and sex-matched control patients. Two radiologists in consensus blinded to surgical history evaluated the intrahepatic ducts qualitatively for dilatation. A single radiologist using the best of three orthogonal planes measured the extrahepatic ducts. Extrahepatic ducts were considered dilated if greater than 7 mm plus 1 mm per decade after 60 years of age. Statistical analysis was performed using t test and chi-square test.

Results: Duct patterns after cholecystectomy were normal ducts in 26% (20/77); intra- and extrahepatic dilation was present in 31.2% (24/77); intrahepatic dilation only was present in 18.2% (14/77); and extrahepatic dilation only was present in 24.7% (19/77) of patients. Duct patterns in the control group were normal for 88.3% (68/77); intra- and extrahepatic dilation was present in 2.6% (2/77); intrahepatic dilation only was present in 2.6% (2/77); and extrahepatic dilation only was noted in 6.5% (5/77) of patients. All cases of intrahepatic ductal dilatation were mild. Total intrahepatic dilation was present in 49.4% of patients after cholecystectomy vs 5.2% of patients in the control group. The relative risk of intrahepatic ductal dilation in patients after cholecystectomy was 9.5:1. Increased prevalence of intra- and extrahepatic dilation in patients after cholecystectomy was statistically significant (p < 0.0001). Average extrahepatic duct was 7.8 mm in patients after cholecystectomy vs 5.3 mm in the control group (p < 0.001).

Conclusion: Mild intrahepatic biliary dilation in the setting of cholecystectomy is very common. If not associated with clinical or biochemical evidence of obstruction, then mild intrahepatic biliary dilation is likely of no clinical significance.