The Estimation of Bladder Volume by Sonocystography

Abstract

Real-time ultrasonography was used to measure bladder volumes [in humans]. Volumes were calculated as the product of 3 internal bladder diameters (height, width and depth). The true bladder volume was obtained from the voided volume or by catheterization. There was a good correlation between calculated and true volumes provided a correction factor of 0.6 was applied. A simpler method using only 2 diameters and a correction factor of 0.15 was nearly as reliable. The accuracy of this quantitative method was shown to be limited to an average error of .+-. 25% for bladder volumes between 100 and 500 ml. Smaller volumes could be assessed only qualitatively. False negative readings were common for bladder volumes less than 50 ml.