Using Observed Contrast Motion During Cardiac Catheterization to Tune Patient Specific Coronary Blood Flow Simulations

In the assessment of coronary artery disease, virtual Fractional Flow Reserve is an emerging technology that uses patient specific of Computational Fluid Dynamics simulations to infer the pressure loss through a stenosis, replacing an effective, but expensive technique based on the use of a pressure wire. To date, most vFFR efforts make use of reduced order lumped parameter models for the inlet and outlet/s of the coronary arterial tree to approximate the patient specific boundary conditions, but suffer from the inability to specify the associated parameters in a patient specific manner. When applying vFFR in a catheter laboratory setting using X-Ray angiograms as the basis for creating the geometrical model, there is some indirect functional information available through observing the motion of the radio-opaque contrast agent. In this work, we present a novel method for tuning the arterial resistances, based on simulating the contrast release and minimising a misfit defined in terms of simulated and observed arrival times of the contrast at multiple points within a coronary tree.