Radiologic and ultrasonographic diagnosis of gallstones

Several new nonsurgical modes of therapy for gallstone disease are being introduced almost simultaneously in the United States. These include orally administered bile acids, contact dissolution with methyl t-butyl ether (MTBE), and extracorporeal shock wave lithotripsy. Paralleling these developments is a similar period of transition in the field of gallstone imaging. Technical considerations in performing ultrasonographic, roentgenographic, and cholecystographic studies become more important, since the criteria for use of the nonsurgical techniques place a greater emphasis on gallstone morphology. In ultrasonography, sizing artifacts from reflective surfaces, optimizing measurements, magnifying hard-copy images, positioning the patient, and optimizing transducer frequencies will need to be addressed. In roentgenography, coned views of the right upper quadrant, with the patient prone, will give the best results. Oral cholecystography (OCG) has largely been replaced by ultrasonography for the detection of gallstones, but it is still an essential part of the imaging workup because it permits adequate visualization of the gallbladder to assure patency of the cystic duct. Correlation of the findings from the several techniques has disclosed new insights and encouraged the use of tailored techniques. Based on the current criteria for the use of orally administered ursodeoxycholic acid, an estimated 60-70% of all patients who have gallstones may be suitable candidates for such treatment.