Craniofacial osseous landmark determination from stereo computer tomography reconstructions.

The accurate and reproducible determination of the three dimensional (3D) co-ordinate positions of anatomical landmarks from computer tomography (CT) images has been limited even though potentially the data have been available for several years. This paper describes a method of acquisition of osseous landmark positions using an off-line computing technique based on multiple stereo images of 3D CT reconstructions. The use of stereo pairs greatly enhances the consistent identification of osseous landmarks. Further, the technique is of particular value where access to the CT scanner is restricted due to heavy clinical demand and separate high quality graphics facilities are unavailable. Osseous landmark position data were determined for dried skulls and patients with craniofacial conditions. Accuracies of the order 1.7mm (median) were obtained. These results encourage the use of the technique for acquisition of landmark positions for the study of the craniofacial complex in three dimensions.