The influence of the spatial structure of focal hepatic lesions on volume measurements performed with two and three-dimensional sonography using the ellipsoid formula.

A total of 63 patients with localized hepatic lesions were examined using two and three-dimensional sonography. The tumor volumes were calculated by means of the ellipsoid formula, compared with an experimentally determined reference volume and subsequently differentiated into correct and erroneous measurements according to the WHO criteria for tumor volumes. In a second test series, an analysis of the tumor shapes was carried out using parallel projections. It could be seen that 65% of the erroneous measurements resulted from the use of the ellipsoid formula, a procedure which is used to determine the volume of hepatic lesions. In the third part of this study, it was found that findings which are difficult to measure are frequently not recognized as such by the investigator making use of two-dimensional sonography. As a consequence, the volume measurements of focal hepatic lesions in oncology patients being considered for particular therapies should preferably be carried out with the aid of planimetric measurements rather than with the use of the ellipsoid formula.