Does computed tomography improve patients selection for extracorporeal shock wave lithotripsy (ESWL) of radiolucent...

In 97 patients with radiolucent solitary gallbladder stones, the density of the calculi was evaluated by computed tomography (CT) prior to extracorporeal shock wave lithotripsy (ESWL). Sixty-three percent of the stones were isodense to bile (mean 48 +/- SD 11 HU), and 37% could be identified on CT-sections (maximal density 105 +/- 46 HU, mean density at the largest cross-section 53 +/- 31 HU). There was a slight trend toward better stone fragmentation and higher clearance rate in patients with isodense stones. However, the probability of complete fragment clearance was not significantly different in stones with a high or low CT-density. From these data we conclude that stone selection for ESWL and adjuvant bile acid therapy in patients with radiolucent solitary stones as assessed by oral cholecystography is only marginally improved by computed tomography.