A Hydrodynamical Study to propose a numerical Index for evaluating the CSF conditions in cerebralventricular system

Background: CSF is a clear liquid that its mechanical properties are to a large extent similar to water properties.

Regarding the lack of a numerical index for diagnosis of diseases resulting from increased CSF pressure such as hydrocephalus, evaluation of hydrodynamic conditions of CSF in cerebral ventricular system is of great importance. Methods: At first, the diagram of velocity in Sylvius aqueduct which was obtained through a 3D FSI analysis in ADINA was compared to the similar diagram extracted from CINE-PC-MRI of the same test subject. The next step after ensuring that the two diagrams coincide with each other, was to make sure that the problem assumptions and solution are correct. Thereafter, the Womersley number in Sylvius aqueduct of a healthy subject was calculated. Results: The amount of this number was 3.25 and indicated the pulsatility of the fluid flow. The difference between the maximum and minimum pressure exerted by CSF on the brain tissue in Sylvius aqueduct was 81.5 Pa. This pressure difference was introduced for the first time in this study as an index for assessing hydrocephalus. Finally, the CSF pressure values calculated in this study and the pressure data obtained from LP test were compared. Conclusion: This comparison showed that utilizing a proper pressure gauge for LP test makes it possible to use the LP test results, alongside with the study results, as an index to assess the CSF conditions in ventricular system for diagnosis of that group of diseases resulting from increase in CSF pressure.