COMPUTATIONAL INVESTIGATION ON CSF FLOW ANALYSIS IN THE THIRD VENTRICLE AND AQUEDUCT OF SYLVIUS

Abstract

In this study, a three dimensional (3D) model of the third ventricle and aqueduct of Sylvius derived from MRI scans was constructed by using Computational Fluid Dynamics (CFD) modeling. Cerebrospinal fluid(CSF) can be modeled as a Newtonian Fluid and its flow through the region of interest (ROI) was visualized using Engineering Fluid Dynamics (EFD).The constructed ROI was regarded as rigid walled and only steady state flow was able to be defined due to the limitations of current software. Different flow rate was simulated at the Foramen of Monro and a small stenosis was modeled at the middle of the aqueduct of Sylvius at a fixed location. This was made corresponding to normal patients with variation of CSF flow rate physiologically and abnormal patients with tumor causing obstruction to or within the aqueduct of Sylvius, respectively. Due to the small dimensions of the ROI geometry, gravity and complex external gravity that acted upon it was considered to be neglected. The results show as the flow rate increase, the pressure drop of CSF in the ROI proportionally increased. For normal CSF flow rate, the presence of stenosis in the aqueduct demonstrates a significant increased pressure drop.

ABSTRAK-Dalam kajian ini, model tiga dimensi (3D) untuk ventrikel ketiga dan akueduk Sylvius, yang terhasil daripada pengimejan resonans magnetik telah dikonstruksi menggunakan Permodelan Perkomputeran Dinamik Bendalir (Computational Fluid Dynamics (CFD)). Cecair serebrospinal (Cerebrospinal fluid (CSF)) dimodelkan sebagai bendalir Newtonan dan alirannya melalui kawasan kepentingan (region of interest (ROI)) digambarkan menggunakan Dinamik Bendalir Kejuruteraan (Engineering Fluid Dynamics (EFD)). Kawasan kepentingan yang dikonstruksi dianggap sebagai dinding tegar dan hanya aliran keadaan tunak yang dapat ditakrifkan berdasarkan pengehadan perisian komputer terkini. Kadar aliran yang berbeza disimulasikan di foramen monro dan laluan stenosis yang kecil dimodelkan di tengah-tengah akueduk Sylvius di satu lokasi yang telah ditetapkan. Kaedah ini dijalankan terhadap pesakit normal dengan variasi pada kadar aliran CSF, serta pesakit abnormal yang mempunyai tumor, penyebab sekatan terhadap atau melinkungi akueduk Sylvius. Disebabkan oleh ukuran geometri ROI kecil, tarikan graviti dan graviti luar kompleks yang bertindak ke atasnya diabaikan. Keputusan menunjukkan bahawa apabila kadar aliran meningkat, susutan tekanan CSF di dalam ROI meningkat dengan berkadar. Untuk kadar aliran CSF yang normal, kehadiran stenosis di dalam akueduk membuktikan pertambahan susutan tekanan yang ketara.