Accuracy and precision of in vitro volumetric measurements by three-dimensional sonography

RATIONALE AND OBJECTIVES. A radiologist often wishes to measure organ volume or monitor changes in internal lesion volume during treatment. If this can be determined via three-dimensional ultrasound, the relative simplicity of the procedure and the decreased cost and known risks to the patient would make this method an attractive alternative to other modalities. METHODS. Three-dimensional ultrasound scans were made of six phantoms: four nonechogenic spheres, one echogenic sphere, and one echogenic, irregularly shaped phantom. A total of 22 volume scans were produced. Volume estimations were made using data from cross-sectional areas and from linear measurements. In all, 193 volume estimations were made. These results were compared with known volumes and with volume estimates from computed tomography scans. RESULTS. Three-dimensional ultrasound detected size differences of 10% with 95% certainty. CONCLUSIONS. The accuracy and precision of volume estimates via three-dimensional ultrasound is at least as good as those obtained via conventional ultrasound.