Visualisation of multimodal images for neurosurgical planning and guidance

Abstract

This paper describes two new methods of rendering multimodal images developed for a neurosurgical planning and guidance system (VISLAN). In our volume rendering technique we introduce a colour dependent filtering mechanism that enhances the representation of objects and improves the visualisation of spatial relationships. To achieve a good compromise between rendering speed and image quality, surface rendering is divided into two processes, a fast surface voxel projection and a surface refining and shading process. By considering the reflections from voxels both near to and on a surface in shading calculations, renderings become less sensitive to small surface extraction errors. A scheme which intermixes the volume rendering for some objects and surface rendering for others in the same scene is also presented. We show examples to illustrate each method in the context of preoperative surgical planning and intraoperative guidance.