3-D segmentation, interpolation and delineation of cortical gyri on MRI data

A method for the delineation of cortical gyri on MRI (magnetic resonance imaging) data is proposed. The method essentially consists of three original algorithms for segmentation, interpolation, and projection of surface information on a planar map. First, a gray-level thresholding is performed on white and gray matter tissues. Second, white matter is automatically segmented with a 3-D connectivity algorithm that accounts for the MRI voxel anisotropy. Third, gray matter is segmented with a local connectivity algorithm. Mathematical morphology tools are used to interpolate slices. The process provides an isotropic binary representation of both gray and white matter that is available for 3-D surface rendering. A brain planar map is then generated by the projection onto an ellipsoid of the distance between the brain surface and its convex hull. Gyri are delineated on the planar development of the ellipsoid and retroprojected on the brain surface.<<ETX>>