IN-VITRO ESTIMATION OF FETAL LIVER VOLUME USING ULTRASOUND, X-RAY COMPUTED-TOMOGRAPHY AND MAGNETIC-RESONANCE-IMAGING

Sixteen formalin-fixed foetal livers were scanned in vitro using a new system for estimating volume from a sequence of multiplanar 2D ultras ound images. Three different scan techniques were used (radial, parall el and slanted) and four volume estimation algorithms (ellipsoid, plan imetry, tetrahedral and ray tracing). Actual liver volumes were measur ed by water displacement. Twelve of the sixteen livers also received x -ray computed tomography (CT) and magnetic resonance (MR) scans and th e volumes were calculated using voxel counting and planimetry. The per centage accuracy (mean +/- SD) was 5.3 +/- 4.7%, -3.1 +/- 9.6% and -0. 03 +/- 9.7% for ultrasound (radial scans, ray volumes), MR and CT (vox el counting) respectively. The new system may be useful for accurately estimating foetal liver volume in utero.