CT evaluation of gallstone calcification for biliary lithotripsy

CT scans were obtained in 20 patients immediately before lithotripsy to evaluate gallstone density. In seven patients, CT showed partial or complete gallstone calcification (>90 HU) not seen on supine abdominal views or oral cholecystograms. In six patients, stones were slightly more dense than bile (>20 HU); in five, stones were isodense (5-20 HU). Lithotripsy fragmentation was excellent or good in four of nine partially or totally calcified stones, in four of six increased density stones, and in two of five isodense stones. In view of the fragmentation of partially or totally calcified stones, as well as less dense stones, calcification may not be a useful criterion for excluding patients from lithotripsy