| Institution: | (1) Institut de Mécanique des Fluides de Toulouse, CNRS UMR 5502, Allées du Professeur Camille Soula, 31400, Toulouse, France;(2) Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA;(3) Engineering Department, Harvey Mudd College, Claremont, CA;(4) Department of Radiology, VA Medical Center, University of California at San Francisco, San Francisco, CA;(5) Institut de Mécanique des Fluides de Toulouse Groupe d Etude sur les Milieux Poreux, Allées du Professeur Camille Soula, 31400, Toulouse Cedex, France |
| Abstract: | Magnetic Resonance Angiography (MRA) has become a routine imaging modality for the clinical evaluation of obstructive vascular disease. However, complex circulatory flow patterns, which redistribute the Magnetic Resonance (MR) signal in a complicated way, may generate flow artifacts and impair image quality. Numerical simulation of MRAs is a useful tool to study the mechanisms of artifactual signal production. The present study proposes a new approach to perform such simulations, applicable to complex anatomically realistic vascular geometries. Both the Navier-Stokes and the Bloch equations are solved on the same mesh to obtain the distribution of modulus and phase of the magnetization. The simulated angiography is subsequently constructed by a simple geometric procedure mapping the physical plane into the MRA image plane. Steady bidimensional numerical simulations of MRAs of an anatomically realistic severely stenotic carotid artery bifurcation are presented, for both time-of-flight and contrast-enhanced imaging modalities. These simulations are validated by qualitative comparison with flow phantom experiments performed under comparable conditions. |
