3D-COMPUTED TOMOGRAPHY - A NEW METHOD FOR THE EVALUATION OF FETAL CRANIAL MORPHOLOGY

This study is the first presentation of three-dimensional computed tom ography (3D-CT) for the in vitro evaluation of the prenatal human cran ium. The study was based on CT examinations from 26 aborted normal fet uses between 10 and 25 weeks gestational age, Incremental coronal and transverse CT slices of 1 mm thickness and a threshold segmentation al gorithm were used to generate 3D-CT reconstructions (surface-shaded di splay, SSD) of the cranial bones similar to their anatomical appearanc e. The threshold of the segmentation algorithm was selected after comp arison of the 3D-CT images generated with varying thresholds and graph ically reconstructed histological serial sections of particular suture s in five specimens. The variation of the segmentation threshold resul ted in alterations of the bone sizes and suture widths. However, 3D-CT images allowed sensitive identification of the cranial ossification c enters and accurate evaluation of the bone topography, Cutting and rot ating procedures made it possible to evaluate all imaged bones in arbi trary views without disturbing superpositions, thus making isolated ex aminations of particular macroscopic sections of the specimens unneces sary. In conclusion, 3D-CT of the fetal cranium promises to be of cons iderable help in the evaluation of prenatal cranial development.