A fast spherical inflation method of the cerebral cortex by deformation of a simplex mesh on the polar coordinates

Abstract

The convoluted shape of the cerebral cortex makes it difficult to analyze and visualize the neuronal activation area. One way of overcoming this problem is to use a spherical inflation method to draw a cerebral cortex on a spherical surface. The task of mapping the cortical surface on a sphere has several obstacles, namely, the overlap between the polygons of the surface, the heavy computation demand, and the geometric distortions inherent in the process. This article proposes a method of mapping the three-dimensional (3D) cortical surface represented in a simplex mesh to a sphere surface, which does not have any overlap between the polygons and minimizes the geometric distortions as well as the computation time. The proposed method consists of the two steps of preprocessing and refinement. In the preprocessing step, the 3D cortical surface is mapped onto a sphere without any overlap between the polygons by iterative deformation. In the refinement step, the mapped surface is adjusted to minimize its linear distortion. The experimental results show the efficiency and performance of the proposed mapping method. (c) 2008 Wiley Periodicals, Inc.