A model for the oscillatory flow in the cerebral aqueduct Articles uri icon

publication date

  • July 2020

start page

  • 1

end page

  • 12

issue

  • R1

volume

  • 899

International Standard Serial Number (ISSN)

  • 0022-1120

Electronic International Standard Serial Number (EISSN)

  • 1469-7645

abstract

  • This paper addresses the pulsating motion of cerebrospinal fluid in the aqueduct of
    Sylvius, a slender canal connecting the third and fourth ventricles of the brain. Specific
    attention is given to the relation between the instantaneous values of the flow rate and
    the interventricular pressure difference, needed in clinical applications to enable indirect
    evaluations of the latter from direct magnetic resonance measurements of the former.
    An order of magnitude analysis accounting for the slenderness of the canal is used
    in simplifying the flow description. The boundary layer approximation is found to be
    applicable in the slender canal, where the oscillating flow is characterized by stroke lengths
    comparable to the canal length and periods comparable to the transverse diffusion time. By
    way of contrast, the flow in the non-slender opening regions connecting the aqueduct with
    the two ventricles is found to be inviscid and quasi-steady in the first approximation. The
    resulting simplified description is validated by comparison with results of direct numerical
    simulations. The model is used to investigate the relation between the interventricular
    pressure and the stroke length, in parametric ranges of interest in clinical applications.

keywords

  • biomedical flows