Morphine-augmented
radionuclide hepatobiliary imaging has been used as an alternative to delayed imaging for the diagnosis of
acute cholecystitis. Previous studies have indicated that the
morphine-augmentation is as useful as, or more useful than, delayed imaging. A careful comparison of the efficacy of the two techniques appears warranted because: (1) most early studies did not compare the efficacy of the two techniques in a single report using comparable patient populations; (2) the reported efficacy of
morphine-augmentation is based primarily on study designs which excluded cases of early gallbladder visualization without
morphine, while most delayed imaging protocols included these cases; and (3) there were concerns about the potential consequences of a false-negative
morphine examination. This study compared the efficacy of
morphine-augmentation with delayed imaging in those cases in which the gallbladder was not visualized during the first hour of study. Of 306 consecutive patients who were scanned to rule out
acute cholecystitis, the gallbladder was visualized within 1 hr in 215 cases. In the remaining 91 cases, 46 patients had delayed imaging (17 true-positive, 10 true-negative, 19 false-positive and 0 false-negative), and 45 had
morphine-augmentation (24 true-positive, 15 true-negative, 4 false-positive and 2 false-negative). The data indicate that delayed imaging has a significantly lower specificity and positive-predictive value for
acute cholecystitis than
morphine-augmentation and a slightly higher (statistically insignificant) sensitivity and negative-predictive value. These results appear to be supported by a reanalysis of the data that has already been reported in the literature.