Quantification of the Dynamics of the Vascular Flows in the Cerebral Arterial and Venous Trees.

Cerebral vascularization is made of the symmetrical arterial system, with muscular walls, and the venous system, more variable and dominated by sinuses and jugular veins. Factors like age and posture influence this network, complicating its study. Phase-contrast MRI is the gold standard for quantifying cerebral circulation. This study aimed to quantify the dynamics of the cerebral blood system using PC-MRI. Thirty-six healthy adults participated. Imaging was performed on a 3T MRI (Philips Achieva) in a supine position. Two slices were acquired: intracranial and extracranial. In-house software analyzed flow curves over a cardiac cycle. Each vessel's contribution was evaluated. Extracranial venous drainage was categorized as jugular-dominant, equivalent, or peripheral-dominant. A similar classification applied intracranially. Intracranial flows showed low variability (5-9%), while extracranial venous flows, especially in the internal jugular veins, had higher variability (17-21%). Some extracranial veins were absent. There is significant venous heterogeneity in the extracranial region. PC-MRI enables the quantification of cerebral dynamics.