Pharmacologic intervention for the diagnosis of acute cholecystitis: cholecystokinin pretreatment or morphine, or both?

Abstract

Recent data and reanalysis of the literature suggest that nonvisualization of the gallbladder on the delayed images of cholescintigraphy is a nonspecific finding. Morphine augmentation has a reasonably good, though imperfect, specificity and positive predictive value, that are significantly better than for delayed imaging, in addition to its logistical advantage (shortening the imaging time). The technique is recommended, therefore, for routine clinical use in patients with nonvisualization of the gallbladder at 1 hr. Further study seems to be necessary to assess the effect of variable or no visible effect of low-dose morphine among patients on the efficacy of morphine-augmented cholescintigraphy. Sincalide pretreatment, when administered at the physiologic rate, is helpful in conditions in which functional resistance to tracer flow into the gallbladder are present. The results from the series by Chen et al. and by Kim et al. suggest that morphine augmentation can further improve the efficacy of the test even after CCK pretreatment. A comparison between the efficacy of delayed imaging and that of imaging for 60-90 min after CCK pretreatment is not available. Therefore, the latter does not obviate the need for delayed imaging when the morphine augmentation technique is not used. Finally, the nuclear medicine physician should use the most optimal technique for the pharmacologic intervention, in other words, the dose and the rate of administration. Certain conditions and medications may affect gallbladder contraction. It is also important to be aware of the various physiologic and pharmacologic effects on imaging findings, not only those findings that are normal but also the undesirable variants. Failure to recognize such effects can lead to incorrect interpretations.