Three-dimensional measurement of liver volume by the rotation method: In vitro study

Background: The multiplane transesophageal echocardiographic (TEE) probe provides a stable position that allows rotation around a central axis to record high-resolution cross-sectional images. The purpose of this study was to use this probe to evaluate the accuracy of a three-dimensional (3-D) volume-calculating algorithm developed in our laboratory to quantify phantom volumes. Method: Ten irregular-shaped phantom specimens were assessed. Cross- sectional images (range of rotation, 0°-160°) were obtained using 20°rotational sections with a multiplane TEE probe. The images were digitized and reconstructed, and the volumes computed. These computed volumes were compared with actual volumes, measured using a volumetric bottle, by linear regression analysis. The interobserver reproducibility was also evaluated. Results: In this experiment, the measured volumes of the phantom specimens ranged from 21 to 118 ml. The computed volumes correlated well with the actual volumes (r = 0.97). The mean error in calculating volume was only 4.3 ml. An excellent correlation for the interobserver reproducibility was also noted (r = 0.95, p < 0.001). Conclusion: The 3-D algorithm we developed enabled us to accurately calculate the volumes of irregularly shaped specimens. Further studies using animal hearts are needed to validate the use of this algorithm for cardiac volume measurement.