Enhancing magnetic resonance imaging with CFD: in vitro validation and patient specific application

Cardiovascular diseases (CVDs) are the main cause of death globally, taking the lives of 17.9 million people every year. The study of blood flow in the great thoracic arteries plays a crucial role in the diagnosis and prevention of CVDs. Flow-sensitive fourdimensional Magnetic Resonance Imaging (4D Flow CMR) has increasingly been utilised to characterise patients’ blood flow in the clinical environment. Nevertheless, spatial and temporal resolutions are still limited to enable a detailed assessment of the haemodynamics quantities. Computational fluid dynamics (CFD) is a powerful tool that has the potential to expand this information and, when integrated with experimentally-obtained velocity fields, enables to derive all the fluid dynamics descriptors of interest. However, the accuracy of the computed flow parameters is necessarily limited by the limited resolution of the 4D MRI, and highly influenced by the boundary conditions imposed. We propose a novel approach in which 4D Flow CMR and CFD-computed velocity fields are integrated synergistically in order to obtain an enhanced 4D Flow CMR imaging (EMRI). The approach was validated in-vitro against 2D particle image velocimetry (PIV) data on an idealised mock aortic arch, subject to pulsatile flow conditions, and tested on a patient specific aorta.