ON THE PULSATILE NATURE OF INTRACRANIAL AND SPINAL CSF-CIRCULATION DEMONSTRATED BY MR-IMAGING

Cerebrospinal fluid (CSF) flow was studied in 24 healthy volunteers us ing gated MR phase imaging. The subarachnoid space (SAS) was divided i nto 5 compartments depending on the magnitude of the pulsatile CSF flo ws: a high velocity compartment in the area of the brain stem and spin al cord, 2 slow ones at the upper and lower extremes of the SAS, and f inally 2 intermediate velocity compartments in between. The main pulsa tile spinal flow channel had a meandering pattern. The extraventricula r CSF-circulation can be explained by pulsatile CSF flow without the n ecessity of assuming existence of a net flow. A successive time offset during the cardiac cycle has been found in the fronto-occipital direc tion of the interplay between the arterial expansion, brain expansion, volume changes of the CSF spaces and of the veins. It is proposed to name this time offset the intracranial ''volume wave'' (VoW).