A geometric method for automatic extraction of sulcal fundi

Sulcal fundi are 3D curves that lie in the deepest regions of the cerebral cortex. Sulcal fundi are often used as landmarks for downstream computations in brain imaging. We present a sequence of geometric algorithms to automatically extract the sulcal fundi from magnetic resonance images and represent them as smooth polylines lying on the cortical surface. First we compute a geodesic depth measure for each point on the cortical surface. Based on the depth information, we extract sulcal regions by checking the connectivity above some depth threshold. We extract endpoints of the fundi and then compute the sulcal fundi by thinning each connected region with the endpoints fixed. The so found curves are then smoothed using weighted splines on surfaces to yield a high quality representation of the sulcal fundi. 1