Classification of congenital abnormalities of the CNS.

A classification of congenital cerebral, cerebellar, and spinal malformations is presented with a view to its practical application in neuroradiology. The classification is based on the MR appearance of the morphologic abnormalities, arranged according to the embryologic time the derangement occurred. The normal embryology of the brain is briefly reviewed, and comments are made to explain the classification. MR images illustrating each subset of abnormalities are presented.