The monitoring of intracranial pressure (ICP) fluctuations, which is needed in the context of a number of neurological diseases, 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.  Systematically derived simplified models relating the ICP fluctuations with the resulting CSF flow rate can be useful in enabling indirect evaluations of the former from non-invasive magnetic resonance imaging (MRI) measurements of the latter. As a preliminary step in enabling these  predictive  efforts,  a  model  is  developed for  the  pulsating  viscous  motion of  CSF  in  the  spinal  canal,  assumed  to  be  a  linearly  elastic  compliant  tube  of  slowly varying section, with a Darcy pressure-loss term included to model the fluid resistance introduced  by  the  trabeculae,  which  are  thin  collagen-reinforced  columns  that  forma  weblike  structure  stretching  across  the  subarachnoid  space  (SSAS).  Use  of  Fourier-series  expansions  enables  predictions  of  CSF  flow  rate  for  realistic  anharmonic  ICP fluctuations. The flow rate predicted using a representative ICP waveform together with a realistic canal anatomy is seen to compare favorably with in-vivo phase-contrast MRI measurements at multiple sections along the spinal canal. The results indicate that the proposed model, involving a limited number of parameters, can serve as a basis for future quantitative analyses targeting predictions of ICP temporal fluctuations based on MRI measurements of spinal-canal anatomy and CSF flow rate.

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