Towards Real-Time 3D Coronary Hemodynamics Simulations During Cardiac Catheterisation

Stephen Moore, Kerry Halupka, Sergiy Zhuk
IBM Research


Abstract

Virtual Fractional Flow Reserve (vFFR) is an emerging technology that assesses the severity of coronary stenosis by means of patient specific of Computational Fluid Dynamics simulations. For application within a catheter laboratory, simulation time is crucial. To be of practical clinical utility, FFR results must be obtainable within minutes. Given the significant compute time required for solution of the full unsteady 3D Navier-Stokes equations, current efforts are either applied at earlier stages of the clinical care pathway (where time is less of a concern), or solve simplified reduced order models (where the compute time is trivial by comparison). With the emergence of powerful Graphics Processing Units (GPUs) and multicore processors, the acceleration of fluid models such as the Lattice-Boltzmann Method (LBM) present another potential option for providing 3D hemodynamics simulations in a suitable timeframe. To this end, we present the design of a novel LBM code specifically tailored for fully automatic near real-time coronary blood flow simulations. The key contributions of the work include a hybrid multicore-GPU accelerated lattice generation algorithm that produces a novel compressed sparse lattice structure and avoids any memory allocation for non-fluid lattice sites (a challenge for structures such as arterial trees). A specialized hemodynamics solver that operates on the sparse lattice structure then performs the fluid simulation and extraction of FFR values along the tree structure, completing the pipeline. ­­­­­­­We present results on a multi segment coronary arterial tree showing that the lattice generator can create millions of lattice sites in the order of seconds and the hemodynamics solver ­can perform a full 3D fluid simulation in the order of minutes, making the replacement of pressure wire based FFR in a catheter laboratory setting with vFFR simulations  feasible, without the need to reduce the fidelity of the hemodynamics modelling.