Gallbladder Volume and Contraction Measured by Sum-of-Cylinders Method Compared with Ellipsoid and Area-Length Methods

Abstract

Gallbladder volume, determined by ultrasonography (US) using the sum-of-cylinders (SOC) method, is tedious and time-consuming. We therefore examined whether ellipsoid (ELL) or area-length (A-L) methods, which are easier to perform, could reliably replace the SOC method. Fasting gallbladder volume and emptying were determined according to these 3 methods in 20 normal subjects and 20 gallstone patients. Excellent correlations were found but the ELL method yielded significantly larger mean volumes and the A-L method revealed significantly smaller volumes than the SOC method. Analysis of differences between methods revealed a considerable lack of consistency. Volumes according to the ELL method were 35 percent larger to 46 percent smaller for normal subjects and 34 percent larger to 41 percent smaller for gallstone patients than volumes according to the SOC method. Volumes according to the A-L method were 35 percent larger to 15 percent smaller for normal subjects and 51 percent larger to 17 percent smaller for gallstone patients. Maximal decrement of gallbladder volume in ml and in percentage according to the 3 different methods did not differ. Regardless of the method used, both fasting and minimal gallbladder volumes were significantly larger in gallstone patients than in normal subjects, whereas maximal decrement of gallbladder volume in ml and percentage was not different. The present study indicates that the SOC method remains the method of choice for US determination of gallbladder volume for scientific purposes.