Real-time ultrasonography as a noninvasive tool for the examination of canine gallbladder emptying: a validation study.

An ultrasonographic measurement of the gallbladder volume based on an ellipsoid approximation of the gallbladder shape was validated in vivo in the dog. The mean difference between the ultrasonographically determined and the true gallbladder volumes amounted to 2.0 +/- 1.6 cm3 (mean +/- SD), whereas the regression line computed for the ultrasonographically measured versus true gallbladder volumes was y = 0.892x + 3.0, r = 0.955, p much less than 0.001. The ultrasonographic method enabled a noninvasive, repetitive measurement of either a meal- or caerulein-induced gallbladder emptying in the dog.