MR Measurement of Cerebrospinal Fluid Velocity Wave Speed in the Spinal Canal

Abstract

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.

A numerical investigation of waves propagating in the spinal cord and subarachnoid space in the presence of a syrinx

“…For entry into ADINA, these viscoelastic properties were translated into equivalent values of viscoelastic shear and bulk moduli. These choices gave significant energy dissipation and a principal wavespeed of slightly over 7 m s À1 , comparable with what has been measured using magnetic resonance imaging in vivo for the spinal cord (Kalata et al, 2009). The cord properties were maintained unchanged as the crosssection tapered inwards at the caudal end, but the ligamentous filum terminale was given the same properties as the dura.…”

A computational model of the cerebrospinal fluid system incorporating lumped-parameter cranial compartment and one-dimensional distributed spinal compartment

“…The speeds of the two waves can be calculated as eigenvalues of the governing system of equations (3) [26]; for the parameters used in the model they amount to roughly 7 and 14 m/s, which is consistent with the estimates from the in vivo measurements [35]. Given the length of the spinal column, this means that only the inputs of several Hz or higher can lead to wave-type behaviour in the spinal CSF.…”

Cerebrospinal Fluid Flow Dynamics in the Central Nervous System

“…This value matches other published values of wave speeds in the spinal canal. A summary of six independent studies of wave speed measurements was recently published by Kalata et al 25 Half of the studies reported a wave speed in the spinal canal of about 4 m/s. As discussed by these authors, in studies reporting values higher than 4 m/s there may have been significant experimental errors.…”

“…Some researchers claim that the pressure wave speed in the spinal canal may be an indicator of pathological changes in the CNS. 9,18,25 The wave speed was calculated by first noting the time at which peak pressures occur in three different locations of the spinal canal. Figure 9 shows that the peak pressure in the upper region occurs at 2% of the cardiac cycle and that peak pressures in the middle and lower regions occur at 4 and 22%, respectively.…”