CHOLESCINTIGRAPHY IN THE DIAGNOSIS OF ACUTE CHOLECYSTITIS - MORPHINE AUGMENTATION IS SUPERIOR TO DELAYED IMAGING

Morphine-augmented radionuclide hepatobiliary imaging has been used as an alternative to delayed imaging for the diagnosis of acute cholecys titis. Previous studies have indicated that the morphine-augmentation is as useful as, or more useful than, delayed imaging. A careful compa rison of the efficacy of the two techniques appears warranted because: (1) most early studies did not compare the efficacy of the two techni ques 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 witho ut morphine, while most delayed imaging protocols included these cases ; and (3) there were concerns about the potential consequences of a fa lse-negative morphine examination. This study compared the efficacy of morphine-augmentation with delayed imaging in those cases in which th e gallbladder was not visualized during the first hour of study. Of 30 6 consecutive patients who were scanned to rule out acute cholecystiti s, the gallbladder was visualized within 1 hr in 215 cases. In the rem aining 91 cases, 46 patients had delayed imaging (17 true-positive, 10 true-negative, 19 false-positive and 0 false-negative), and 45 had mo rphine-augmentation (24 true-positive, 15 true-negative, 4 false-posit ive and 2 false-negative). The data indicate that delayed imaging has a significantly lower specificity and positive-predictive value for ac ute cholecystitis than morphine-augmentation and a slightly higher (st atistically 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.