3-DIMENSIONAL ULTRASOUND - ACCURACY OF DISTANCE AND VOLUME MEASUREMENTS

The aim of this study was to evaluate the accuracy of three-dimensiona l ultrasound distance and volume measurements using a commercially ava ilable three-dimensional ultrasound scanner. Sixty-two distance measur ements were performed twice on an ultrasound tissue-mimicking phantom located in a water bath. Three-dimensional ultrasound distance measure ments were compared to She actual distance. Volume measurements were m ade in a water bath with 21 balloons of various shapes ranging in volu me from 20 mi to 490 mi. Three-dimensional ultrasound volume measureme nts were compared to actual balloon volumes and to conventional two-di mensional ultrasound volume calculations. The mean absolute error in t hree-dimensional ultrasound distance measurements was 1.0 +/- 0.8% (ra nge, -2.3 to +1.9%) in the plane of acquisition and 1.0 +/- 0.6% (rang e, -2.0 to -0.2%) for planes with other orientations. Three-dimensiona l ultrasound volume measurements showed a mean absolute error of 6.4+/ -4.4% (range, -6.0% to +15.5%), which was considerably better than two -dimensional ultrasound volume estimates having a mean absolute error of 12.6+/-8.7% (range, -27.5% to +39.2%). Volume measurements using tw o-dimensional ultrasound methods were much less accurate than three-di mensional ultrasound methods for irregularly shaped objects. In conclu sion, our data show that three-dimensional ultrasound measurements of distance and volume are sufficiently accurate to use clinically.