Origin of subarachnoid cerebrospinal fluid pulsations: a phase-contrast MRanalysis

Cerebrospinal fluid (CSF) pulsations result from change of blood volume in the closed craniospinal cavity. We used cine phase contrast MR analysis to determine whether spinal CSF pulsations result from spinal vascular pulsati ons or intracranial subarachnoid pulsations, whether intracranial CSF pulsa tions result from intracranial large arteries pulsations or cerebrovascular bed changes. We performed a quantified physiological mapping of CSF veloci ty waveforms along the craniospinal axis. Thirty-six volunteers participate d in the study. MR acquisitions were obtained at the intracranial level, th e upper, midcervical, cervicothoracic, mid thoracic, and/or the thoracolumb ar levels. The temporal velocity information were plotted as wave form and key temporal parameters were determined and analyzed; intervals from the R wave to the onset of CSF systole, to CSF systolic peak, to the end of systo le, as well as duration of systole. Three kinds of dynamic channels could b e differentiated along the spinal axis, the lateral, medioventral and medio dorsal channels. Lateral spinal CSF pulse waves show significant craniocaud al propagation. No such significant progression was detected through the me dial channels along the spine. Through the medial channels, a cephalic prog ression was observed from the upper cervical level to the intracranial leve l. At the craniocervical junction, mediodorsal CSF systole appeared the ear liest one whereas in the anterior intracranial basal cistern, CSF systole a ppeared delayed. In conclusion, spinal CSF pulsations seem to result mainly from intracranial pulsations in the lateral channels, whereas local vascul ar pulsations could modify CSF pulse wave mainly in the medial channels. At the craniocervical junction, our results suggest that blood volume change in the richly vascularised cerebellar tonsils is the main initiating factor of CSF systole; and that spinal vascular pulsations could be considered as an additional early and variable CSF pump. (C) 2000 Elsevier Science Inc. All rights reserved.