Abnormalities of the gallbladder after extracorporeal shock-wave lithotripsy: imaging findings

To qualify for treatment with biliary extracorporeal shock-wave lithotripsy (ESWL), patients must have sonograms that show gallstones and oral cholecystograms (OCGs) that show normal opacification (indicating normal function) of the gallbladder. We have noted that sonograms and OCGs made 6 weeks to 6 months after ESWL sometimes show abnormalities that were not visible on these images before ESWL. In these cases, the gallbladder appears contracted on sonograms and is poorly visualized on OCGs. To determine how often this occurs and to study its significance, we analyzed the posttreatment sonograms and OCGs in 174 patients who underwent ESWL. After ESWL, sonograms showed a contracted gallbladder and OCGs showed poor function in 25 (14%) of the 174 patients. One patient (4%) was lost to follow-up. In 17 (68%) of the 25 patients, the abnormalities were transient (findings on sonograms and OCGs returned to normal by 12 months after ESWL). In the other seven patients (28%), the abnormalities persisted (all seven subsequently had a cholecystectomy); this is a cholecystectomy rate twice that in the patients with normal findings on sonograms and OCGs after ESWL (20/149 or 13%). All 25 patients with abnormalities after ESWL had gallstone fragments at 6 weeks, as did 146 of the 149 patients with normal-appearing gallbladders after ESWL. When these abnormalities persist (in approximately one third of patients), cholecystectomy is often required. The cause of the abnormalities is unknown, although chronic cholecystitis, a process that is not detectable by pre-ESWL imaging techniques, seems likely.