A Simple Method for Computing the Volume of the Human Gallbladder

The lack of understanding that prevails in the field of motor dysfunctions of the gallbladder—we might better say, of the extrahepatic biliary system, to which it belongs—is in large part dependent upon three factors: 1. Deficient knowledge of the physiology of the extrahepatic biliary system, a matter which only in recent decades is receiving substantial elucidation. 2. Lack of standardization in radiological technics applied to the study of the process of discharge of gallbladder contents, especially in that part dealing with the cholecystokinetic meal, and the intervals and length of time in which the evacuation is observed. 3. Absence of numerical data in most studies of the emptying of the gallbladder. Reading the articles on motor function of the gallbladder published since the onset of the cholecystographic era, one is amazed to find two really different systems of approaching the subject: on one hand, that of Boyden and his co-workers, using a definite method of study and a procedure for estimating the volume of the gallbladder for more than twenty years; on the other hand, a variety of heterogeneous technics, without numerical criteria to evaluate the course of emptying. A method for determining the volume of the gallbladder was presented by Boyden (1) in 1926. It is hard to understand why such a method has not been systematically used by all authors that have treated the subject. Without an adequate method and with no basis of measures and numbers, they have lost themselves in the slippery field of adjectives and variable impressions. Boyden wrote in 1926: “A graphic method of computing the volumes, suggested to the writer by Prof. E. T. Adams, of the Department of Biochemistry, was finally selected as the quickest and most accurate method. In theory this consisted of establishing the longitudinal axis of the cholecystogram and then determining the diameter at every fifth of an inch or less. The volume of the successive plinths could then be obtained by using the formula πD2/4, D being the length of a perpendicular. When added together these volumes gave the total amount of bile in the gallbladder. The application of the graphic method to this problem consisted in laying out a curve on co-ordinate paper so prepared that when successive D's were transferred to ordinates and the corresponding abscissas plotted on co-ordinate paper, the area thus outlined, when measured with a planimeter, automatically gave the volume of the gallbladder in cubic inches.” After this mention of the procedure for computing the volume of the gallbladder, Boyden (2) received so many requests for information that he decided to give an example in an appendix to his work on the reaction of the human gallbladder to food. This was written by Prof. E. T. Adams. There is shown a tracing of a gallbladder shadow bisected longitudinally. A parallel CD to the axis (AB) of the gallbladder is drawn. A series of perpendiculars to these two parallel lines are traced.