Particle Trace Visualization of Flow Patterns Downstream of a Prosthetic Aortic Valve in Patients

Introduction Late complications such as hemolysis and thrombus formation in patients with an implanted prosthetic heart valve have been related to fluid dynamic characteristics [ 11. Specific blood flow patterns such as flow reversal and vortex flow have been considered to contribute to thrombus formation [2]. In order to detect alterations of flow fields around prostheses in humans MR velocity mapping might be a powerful modality. Furthermore in-vivo data would help to verify current in-vitro and numerical experiments used for the development of prosthetic valves. Two-dimensional time-resolved velocity distributions around a mechanical heart valve have already been studied with MRI in humans [3]. However the three-dimensional nature of flow downstream of prosthetic valves remains poorly defined as measured with two-dimensional methods. To assess three-dimensional flow patterns downstream of the St. Jude Medical aortic valve in patients particle trace visualization of data obtained with a tine navigator gated 3D phase contrast sequence is presented.