Nerve pathways with MR tractography

The neuroradiological interpretation of magnetic resonance (MR) images relies on a complex semeiotics that is based on the morphological and signal characteristics of normal and pathological brain and on the detailed knowledge of the ultrastructural and functional organization of the central nervous system (CNS). The study of the brain's cortical organization is facilitated by the presence on its surface of fissures that divide it into lobes and sulci that circumscribe in each lobe a number of convolutions or gyri. Identification of the encephalic nuclei, greymatter formations lying deep in the hemispheres, is also facilitated by their characteristic morphology, their symmetric position with respect to the midline, and the presence of specialized white structures such as the internal, external and extreme capsule that mark their borders.