Ultrasonographic study of the biliary system in opisthorchiasis patients after treatment with praziquantel.

Ultrasonographic examination of the liver and biliary system using a portable ultrasound unit was performed in 1987 in 647 opisthorchiasis patients who had been treated with praziquantel during 1981 to 1986. Treatments was repeated annually in those reinfected. The reinfection rate was 53.9% in the first year and gradually declined. Ultrasonographic findings were normal in 80.6% of subjects. The most common abnormal finding was liver enlargement (14.8%), followed by dilatation of the gallbladder (3.5%), sludge formation (2.1%) and thickening of the wall of the gallbladder (1.0%). Gallstones were found in 7 cases (1.0%). Dilatation of intrahepatic bile ducts was detected in one subject (0.1%). The incidence of gallstones in treated patients was similar to that reported in a large necropsy series of the general population. Prospective studies will be needed to further investigation the association between opisthorchiasis, treatment and gallstone formation.