The trans-cerebral veins: normal and non-pathologic angiographic aspects.

The trans-cerebral v. have long been described, but there is little or no knowledge of their function and dysfunction. They are the site of fundamental interchange across the blood-brain barrier, a unique process within the organism. Two systems can be structurally distinguished: the venous system draining the white matter and the trans-cerebral anastomotic system. The former seems to be associated with the nutrition and drainage of the parenchyma, and is rendered visible at angiography by anatomic variations based on developmental venous anomalies. The anastomotic trans-cerebral ventriculo-cortical system seems concerned with the regulation of reabsorption of the cerebrospinal fluid. It is visualized only in exceptional situations where an increased flow (arteriovenous shunt) is combined with obstruction of the normal routes of venous drainage and collateral circulation. It usually functions in the ventriculo-cortical direction. No specific dysfunction of this system is currently recognized.