Toward non-invasive intracranial pressure evaluation using a 1D model for the pulsating flow of cerebrospinal fluid in the spinal canal

Continuous intracranial pressure (ICP) monitoring is key in the assessment of surgical intervention and guiding therapy for certain neurological diseases, but requires the insertion of pressure sensors, an invasive procedure with considerable risk factors. ICP fluctuations drive the wave-like pulsatile motion of cerebrospinal fluid (CSF) along the compliant spinal canal. A simple 1D model was developed for the pulsating viscous motion in the spinal canal assuming a linearly elastic compliant tube of slowly varying section, with a Darcy pressure-loss term included to model the fluid resistance introduced by the microanatomy. Use of Fourier-series expansions enables predictions of the CSF flow rate for realistic anharmonic ICP fluctuations. Here we explore the effect of the ICP signal morphology on the resulting flow rates to compare to measured flow rates from MRI. We also use the range of determined physiological parameters to perform the inverse problem using the flow rate to estimate the temporal variation of the ICP.