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

• Published in: Medical & biological engineering & computing Vol. 55; no. 9; pp. 1605 - 1619
• Main Authors: Mohd Adib, Mohd Azrul Hisham, Ii, Satoshi, Watanabe, Yoshiyuki, Wada, Shigeo
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2017; Springer Nature B.V
• Subjects: Aneurysm; Aneurysms; Angiography; Arteries; Bifurcations; Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Biomedicine; Boundary layers; Computational fluid dynamics; Computer Applications; Computer simulation; Digital imaging; Flow velocity; Fluid dynamics; Hemodynamics; Human Physiology; Hydrodynamics; Image contrast; Image reconstruction; Imaging; Integration; Magnetic resonance imaging; Mechanical stimuli; NMR; Nuclear magnetic resonance; Original Article; Personal computers; Pressure; Radiology; Resonance; Shear stress; Simulation; Velocity; Cerebral aneurysm; Computational fluid dynamics; Pressure boundary condition; Phase-contrast magnetic resonance imaging; Measurement integrated simulation
• ISSN: 0140-0118; 1741-0444
• DOI: 10.1007/s11517-017-1617-y

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.