MR measurement of cerebrospinal fluid velocity wave speed in the spinal canal

Noninvasive measurement of the speed with which the cerebrospinal fluid (CSF) velocity wave travels through the spinal canal is of interest as a potential indicator of CSF system pressure and compliance, both of which may play a role in the development of craniospinal diseases. However, measurement of CSF velocity wave speed (VWS) has eluded researchers primarily due to either a lack of access to CSF velocity measurements or poor temporal resolution. Here, we present a CSF VWS measurement methodology using a novel MR sequence that acquires unsteady velocity measurements during the cardiac cycle with a time interval < 10 ms. Axial CSF velocity measurements were obtained in the sagittal plane of the cervical spinal region on three subjects referred for an MRI scan without craniospinal disorders. CSF VWS was estimated by using the time shift identified by the maximum velocity and maximum temporal velocity gradient during the cardiac cycle. Based on the maximum velocity gradient, the mean VWS in the three cases was calculated to be 4.6 m/s (standard deviation 1.7 m/s, p < 0.005) during systolic acceleration. VWS computed using maximum velocity alone was not statistically significant for any of the three cases. The measurements of VWS are close in magnitude to previously published values. The methodology represents a new technique that can be used to measure VWS in the spinal canal noninvasively. Further research is required to both validate the measurements and determine clinical significance.