A system for analyzing a brain ventricle (8) is described. The system comprises an edge detector (52) for identifying an edge point (17) on an edge of the brain ventricle. Also, a length measurer (53) is provided for establishing a length measure of a path (10) starting from a central point (5) of the brain ventricle and terminating at the edge point (17). The edge detector (52) is arranged for detecting an edge point at an end of a lobe of the brain ventricle, the length measure corresponding to an extent of the lobe.