Structures and development of the venous system in congenital malformations of the brain.

Cerebral venograms of 21 clinical cases of midline anomalies of the brain and of 80 human fetuses between 3 and 8 months old were examined. The diagnostic value of the venogram was fully proven, particularly for the midline cerebral anomalies, where deep cerebral structures and configuration of the tentorium cerebelli were not well visualized by other neuroradiologic maneuvers. Abnormal structures of the deep cerebral veins as well as the dural sinuses in these malformations were proved to retain the venous structures in the early fetal period. The time of formation of these malformations was also inferred from the viewpoint of the venous development. Study of the fetal venous system was found quite useful for embryologic analysis and classification of congenital malformations of the brain.