In Vitro Evaluation of an Ultrasonic Three-Dimensional Imaging and Volume System

A method is described for developing three dimensional organ reconstructions and volumes from a series of arbitrarily oriented real time ultrasonic scans. In vitro evaluations of this method assessed the accuracy of three dimensional point determination and the accuracy of volume determination. The overall repeatability error of three dimensional point determination was found to be 0.6 cm in the horizontal direction and 0.3 cm in the vertical direction; most of this error was caused by the ultrasound resolution and errors in the 3D position locator. The accuracy of volume determination was assessed on balloons, kidneys and left ventricular molds. Thirty volume trials on 10 balloons gave 27 out of 30 calculations within 1.8 percent of true volume. Eighteen trials on 6 kidneys gave 17 out of 18 calculations within 5.1 percent of true volume. Fifteen trials on 5 human left ventricular molds gave 13 out of 15 calculations within −5.9 percent of the true volume. It is concluded that this technique provides the potential for accurate non-invasive volumes, for organs such as the heart, kidney or fetus.