Comparative Computational Fluid Dynamics and Experimental Phase-Contrast MRI: Evaluations of In-Stent Restenosis

While angiography and other translesional catheter-based assessments of stented peripheral vasculature are currently used in clinical applications, a quantitative non-invasive imaging modality would improve the treatment of intermediate levels of in-stent restenosis (ISR). The use of magnetic resonance imaging (MRI), in metal stents has been limited due to magnetic susceptibility artifacts and radiofrequency shielding effects. However, MRI compatible materials such as nickel-titanium alloys used in stents have shown superior lumen visibility. In this study, we used phase contrast MRI in a flow phantom of three different geometries of stenosis: a) 90% axisymmetric, b) 75% axisymmetric and c) 50% asymmetric. The velocity distribution was obtained at 3 different locations inside the stent. This was compared with an equivalent computational fluid dynamics (CFD) model of the same stenotic geometries.