Determination of the origin of the extrahepatic bile duct stones by magnetic resonance cholangiography (MRC) / 대한내과학회지

ABSTRACT

BACKGROUND: Extrahepatic bile duct stones can be classified into two types. Primary stones are formed de nevo in the bile duct, whereas secondary stones migrate from the gallbladder into the bililary tree. The differentiation between primary and secondary stones is very difficult before operation. The aim of this study is to determine the origin of extrahepatic bile duct stones by analyzing MRC features. METHODS: MRC was obtained in 38 patients with stones in both the common duct and gallbladder. MRC findings were compared for gross characteristics and MR signal patterns between common duct stone and gallbladder stone pairs. The gross morphologic characteristics of gallstones on MRC were classified into oval, polygonal, round, rod, sandy and mixed shape. Gallstone patterns seen on heavily T2-weighted images were categorized into one of two patterns: dark, and mixed signal. RESULTS: According to the morphologic characteristics on MRC images, the common duct stones were oval (n=9), polygonal (n=15), round (n=6), sandy (n=4), mixed (n=3) and rod (n=1). The visualized MR signal patterns of common duct stones on heavily T2-weighted images were dark (n=28) and heterogenous (n=10). CONCLUSION: On MRC, the gross morphologic characteristics and gallstone patterns of common duct stones were similar to those of their paired gallbladder stones in 60.5 to 78.9% of patients.