Discrepancies between cholecystography and ultrasonography in the detection of recurrent gallstones

As part of the British Gallstone Study Group's multi-centre post-dissolution trial of different treatment regimes designed to prevent recurrence after complete gallstone dissolution, the frequency of concordance and discordance between oral cholecystography (OCG) and ultrasonography (U/S), and between repeat U/S studies, in diagnosing recurrent stones was recorded. Before entering the trial, all patients had had complete gallstone dissolution, confirmed by 2 normal OCGs 3 months apart during continued bile acid treatment; and all but three had also had at least 1 normal U/S examination of the gallbladder. During 6-24 months follow-up, from a total of 129 U/S examinations, gallstone recurrence was detected on 25 occasions (19 definite and 6 probable) in 14 patients, and from a total of 71 OCGs, recurrent stones were detected on 11 occasions in 10 patients. All the presumed recurrences developed in the absence of symptoms. On 67 occasions, the OCG and U/S studies were performed within 8 weeks of each other and of these, there was discordance in 15 (22%). On 11 occasions (6 patients), ultrasound suggested recurrent stones despite a normal OCG whilst on 4 occasions (4 patients) stones diagnosed on OCG were not confirmed by ultrasound. Of the 25 instances of U/S recurrence, a further U/S examination was performed on 17 occasions in 11 patients which failed to confirm the initial findings on 8 occasions (7 patients). After 1 year's follow-up, the predicted recurrence rates (pooled data from all 3 treatment groups), as calculated by life table analysis, were 29.3 +/- 7.1%, when the diagnosis was based on 1 U/S; 15.4 +/- 5.8% on 1 OCG; 14.9 +/- 5.6% on 2 successive U/S studies, and 8.1 +/- 4.5% on 1 U/S plus 1 OCG. At 24 months, the corresponding values were 37.2 +/- 8.3, 31.5 +/- 8.6, 18.3 +/- 6.3, and 22.4 +/- 8.6%. These results show that following complete gallstone dissolution by bile acid treatment, there is both intra- and inter-technique variation in the detection of recurrent stones.