Ultrasonographic evaluation of preprandial and postprandial gallbladder volume in healthy cats

Objective—To noninvasively assess the influence of ingestion of a standard meal on gallbladder volume (GBV) in healthy cats. Animals—10 healthy adult domestic shorthair cats (4 neutered females, 5 neutered males, and 1 sexually intact male). Procedures—Nonsedated cats were positioned in dorsal and left lateral recumbency to obtain ultrasonographic measurements of the gallbladder via the subcostal and right intercostal acoustic windows, respectively. Gallbladder volume was calculated from linear measurements by use of an ellipsoid formula (volume [mL] = length [mm] X height [mm] X width [mm] X 0.52). Measurements were recorded after food was withheld for 12 hours (0 minutes) and at 5, 15, 30, 45, 60, and 120 minutes after cats were fed 50 g of a standard commercial diet (protein, 44.3%; fat, 30.3%; and carbohydrate, 15.6% [dry matter percentage]). Results—Agreement between gallbladder linear measurements or GBV obtained from the subcostal and right intercostal windows was good. Feeding resulted in linear decreases in gallbladder linear measurements and GBV. Via the subcostal and intercostal windows, mean ± SD GBV was 2.47 ± 1.16 mL and 2.36 ± 0.96 mL, respectively, at 0 minutes and 0.88 ± 0.13 mL and 0.94 ± 0.25 mL, respectively, at 120 minutes. Gallbladder width most closely reflected postprandial modification of GBV. Conclusions and Clinical Relevance—Results indicated that ultrasonographic assessment (via the subcostal or right intercostal acoustic window) of postprandial changes in GBV can be used to evaluate gallbladder contractility in cats. These data may help identify cats with abnormal gallbladder emptying.