We developed a three dimensional numerical model for analyzing the pulsatile cerebrospinal fluid (CSF) flow surrounding the human central nervous system (CNS).  The goal was to provide an accurate structured model for further investigation of different aspects of drug delivery to the CNS through CSF for the therapeutic treatment of various diseases. A complete three-dimensional geometry of CNS, including the subarachnoid space around the brain and spinal cord, was reconstructed of the brain and the entire spine using the 1.5 Tesla magnetic resonance images (MRI) of a healthy male volunteer. The MRI images used had a high resolution of 0.5mm spacing between the slices. For avoiding complexity, the nerve roots coming out of the spinal cord were neglected. The simulation results were presented in terms of pressure and flow velocity in different regions and compared with the experimental data in the literature. Also, to investigate the effect of gravity, different simulations were performed to model CSF flow in supine and upright body postures based on the available MRI flow data for the input flow rate of the lateral ventricles, which measured for people who were 21 -27 years old. In addition, a novel and straightforward technique for modeling the brain subarachnoid hemorrhage (SAH) and its effect on the intracranial pressure (ICP) was presented. The three relative maximum points of the (ICP) wave diagram, which are its main characteristics, were captured, and they were shown to be in good agreement with medical literature data. These maxima are known to be due to choroid plexuses pulsation, brain compliance, and heartbeat variations. The obtained simulation results for the pressure and velocity magnitudes for a normal ICP diagram were in good agreement with the in vivo measurement data, which are based on the 4D cine MRI data reported in the literature.

The simulation results also showed that the pressure amplitude in the upright posture is slightly higher compared to that in the supine posture. In contrast, the mean pressure is noticeably higher for the upright posture due to gravity.  The cerebrospinal fluid flow field, however, has not been mainly affected by the posture alone. Also, SAH is modeled by increasing the flow resistance in the sagittal sinus by considering it as a porous region. The numerical results show a higher ICP for SAH case compared to a healthy case as expected. The obtained results quantify the normal intracranial dynamics of CSF flow inside the CNS and also provide the basis for analyzing diseased intracranial dynamics such as different types of stenosis, uncompliant thecal sac, etc. In addition, the present model can be used to investigate the possibility of targeted drug delivery with the mechanism of flow pulsation through the CNS to decrease the drug’s side effect.


Three-Dimensional Numerical Modeling Of Pulsatile Cerebrospinal Fluid Flow Around Central Nervous System

Division / Sponsors: 
Heat Transfer Division (HTD), Fluids Engineering Division (FED)

Heat Transfer Summer Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/HT/HT2020/volume/83709

18th International Conference on Nanochannels, Microchannels, and Minichannels
Paper Proceedings: https://asmedigitalcollection.asme.org/ICNMM/ICNMM2020/volume/83693

Fluids Engineering Division Summer Meeting
Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2020/volume/83716

HT-ICNMM2020 - Virtual Conference, SHTC - Virtual Conference, FEDSM2020 - Virtual Conference

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