Compared with Patient-Specific Computational Fluid Dynamics

BACKGROUND AND PURPOSE: CFD has been proved valuable for simulating blood flow in intracranial aneurysms, which may add to better rupture risk assessment. However, CFD has drawbacks such as the sensitivity to assumptions needed for the model, which may hinder its clinical implementation. 3D PC-MR imaging is a technique that enables measurements of blood flow. The purpose of this study was to compare flow patterns on the basis of 3D PC-MR imaging with CFD estimates. MATERIALS AND METHODS: 3D PC-MR imaging was performed in 8 intracranial aneurysms. Two sets of patient-specific inflow bound-aries for CFD were obtained from a separate 2D PC-MR imaging sequence (2D CFD) and from the 3D PC-MR imaging (3D CFD) data. 3D PC-MR imaging and CFD were compared by calculation of the differences between velocity vector magnitudes and angles. Differences in flow patterns expressed as the presence and strengths of vortices were determined by calculation of singular flow energy. RESULTS: In systole, flow features such as vortex patterns were similar. In diastole, 3D PC-MR imaging measurements appeared inconsis-tent due to low velocity-to-noise ratios. The relative difference in velocity magnitude was 67.6 51.4 % and 27.1 24.9 % in systole and 33.7 21.5 % and 17.7 10.2 % in diastole for 2DCFD and 3DCFD, respectively. For singular energy, this was reduced to 15.5 13.9 % at systole and 19.4 17.6 % at diastole (2D CFD). CONCLUSIONS: In systole, good agreement between 3D PC-MR imaging and CFD on flow-pattern visualization and singular-energy calculationwas found. In diastole, flowpatterns of 3D PC-MR imaging differed from those obtained fromCFDdue to low velocity-to-nois