Comparison of Sonography and Scintigraphy in the Evaluation of Gallbladder Functional Studies With Cholecystokinin

Objective. Both sonography and scintigraphy have been used to evaluate gallbladder function with the use of sincalide (cholecystokinin [CCK]). However, the reported ejection fractions (EFs) for the two modalities are not the same. The techniques measure slightly different parameters. This study directly compared both techniques performed simultaneously on the same participants. Methods. Twenty healthy volunteers were evaluated with sonography and scintigraphy to estimate the gallbladder EF simultaneously. The gallbladder EF was calculated at 5-minute intervals for 1 hour. Results. The mean El's +/- SD were 66.3% +/- 20% and 49% +/- 29% for sonography and scintigraphy, respectively. The mean times to the peak EF were 38 12 and 33 9 minutes for sonography and scintigraphy. An average time of 34 minutes was noted after radiopharmaceutical injection before CCK administration for the scintigraphic studies. The earliest time to the peak EF for sonography was 15 minutes, and the latest time to the peak EF was 60 minutes (mode, 40 minutes); for scintigraphy, the earliest and latest times were 15 and 50 minutes (mode, 30 minutes), respectively. One participant could not be evaluated secondary to nonfilling of the gallbladder on scintigraphy. There was wider variability of the gallbladder EF with scintigraphy than sonography. Conclusions. Scintigraphy estimated a lower EF than sonography, had wider EF variability than sonography, and required additional time (>30 minutes more) to complete the study. Scintigraphy could not be performed in 5% of the participants because of nonfilling of the gallbladder The use of sonography to estimate the gallbladder EF is less time-consuming and less costly. With these techniques, the range of normal gallbladder El's should be adjusted for the technique used.