Bull Nicholas, Goonawardena Janindu, Hua Lina, Lim Dee, Cheung King Tung, Ramachandran Vivek, Fox Adrian, Hassen Sayed
Department of UGI and HPB Surgery, Box Hill Hospital, Box Hill, Victoria, Australia.
Department of Radiology, Box Hill Hospital, Box Hill, Victoria, Australia.
ANZ J Surg. 2024 Dec;94(12):2195-2200. doi: 10.1111/ans.19189. Epub 2024 Aug 5.
Hounsfield unit density of biliary fluid on CT may be a useful clinical marker that has not been described in the literature. This method has been used to differentiate pyonephrosis from hydronephrosis in obstructed collecting systems of the kidney. We aimed to create a user-friendly technique to measure the density of the distal bile duct using CT. The bile duct density of cases with proven choledocholithiasis at ERCP were compared with those of a control group (no biliary pathology).
A total of 106 patients with proven choledocholithiasis at ERCP and 50 control patients were analysed. The distal bile duct density was calculated using the 4-point and max ellipse methods. Two blinded, independent investigators calculated the bile duct density.
The HU is significantly higher in the presence of choledocholithiasis (P < 0.0001). Using the Youden index a cut-off value of 28.6 HU for the 4-point technique is useful to predict the presence of choledocholithiasis (Sensitivity 58%, Specificity 86%).
Calculation of the distal bile duct density can differentiate choledocholithiasis from a control population. It may be useful alone or as a component of a scoring system to select patients more effectively for intervention. The improved use of CT may also decrease use of MRCP and reduce time to ERCP, which have potential cost benefits.
