Modelization and Three-Dimensional Visulation of the Carpus From CT Slices

This paper presents a method of 3D modelization of the bones of the carpus from a set of CT slices. This modelization allows to process a 3D segmented visualization of the wrist. Many authors have studied the way of computing images of 3D data by so called "volume rendering" or "ray tracing" techniques [6, 7]. The major drawback of these approaches is that they cannot process independently the different objects appearing in the volume. Our method separates the bones of the wrist, allowing to render surfaces hidden by other bones or to evaluate precisely the location and the shape of a fracture. This technique of visualization is based on a first step of modelization of the bones. In order to isolate the bones one from the other, we apply a segmentation technique to the set of slices, producing a set of contours. To classify these contours into different bones, we use a proximity criterion based on the computation of their best approximation ellipses which allows to build an adjacence graph of the contours. Then, a bone is modelized as a connex component of this graph. This gives a wireframe representation of the bones. The external surfaces can then be approximated by triangulation or spline interpolation and visualized by classical rendering algorithms.