Minimizing the blood velocity differences between phase-contrast magnetic resonance imaging and computational fluid dynamics simulation in cerebral arteries and aneurysms

Abstract

The integration of phase-contrast magnetic resonance images (PC-MRI) and computational fluid dynamics (CFD) is a way to obtain detailed information of patient-specific hemodynamics. This study proposes a novel strategy for imposing a pressure condition on the outlet boundary (called the outlet pressure) in CFD to minimize velocity differences between the PC-MRI measurement and the CFD simulation, and to investigate the effects of outlet pressure on the numerical solution. The investigation involved ten patient-specific aneurysms reconstructed from a digital subtraction angiography image, specifically on aneurysms located at the bifurcation region. To evaluate the effects of imposing the outlet pressure, three different approaches were used, namely: a pressure-fixed (P-fixed) approach; a flow rate control (Q-control) approach; and a velocity-field-optimized (V-optimized) approach. Numerical investigations show that the highest reduction in velocity difference always occurs in the V-optimized approach, where the mean of velocity difference (normalized by inlet velocity) is 19.3%. Additionally, the highest velocity differences appear near to the wall and vessel bifurcation for 60% of the patients, resulting in differences in wall shear stress. These findings provide a new methodology for PC-MRI integrated CFD simulation and are useful for understanding the evaluation of velocity difference between the PC-MRI and CFD.

A perspective review: Technical study of combining phase contrast magnetic resonance imaging and computational fluid dynamics for blood flow on carotid bifurcation artery

“…Moreover, the configuration and position of shearing velocity in PC-MRI integrated with CFD were similar in term of flow direction as reported by Isoda et al [95]. Furthermore, Mohd Adib et al, [96] claimed that lowvelocity difference was achieved with velocity-field-optimized (V-optimized) approach and they also introduced a physically consistent feedback control-based data assimilation (PFC-DA) method [97] to improve blood flow analysis by coupling the body force with the pressure boundary condition, but there was still 20% of deviation on the velocity difference.…”

Comparison of intracranial aneurysm flow quantification techniques: standard PIV vs stereoscopic PIV vs tomographic PIV vs phase-contrast MRI vs CFD

“…When CFD results are compared with measurement data (see Augsburger et al 23 for a review) the most patient-specific validation database can certainly be obtained by in-vivo flow measurements conducted by phase-contrast magnetic resonance imaging (PC-MRI), see eg, Boussel et al 11, Berg et al 12, and Mohd Adib et al 13. However, this technique still suffers from relatively poor resolution, which might be an important limitation with respect to the small dimensions commonly encountered with cerebral aneurysms.…”

Study of Extracted Geometry Effect on Patient-Specific Cerebral Aneurysm Model with Different Threshold Coefficient (Cthres)

“…The fluid, blood is considered as incompressible, laminar, Newtonian fluid with isothermal constant viscosity of 0.0035 Pa.s [23]. The blood density is 1060 kg/m 3 [24] with reference to the average normal human blood density.…”