Spatial resolution and velocity field improvement of 4D‐flow MRI

Purpose 4D‐flow MRI obtains a time‐dependent 3D velocity field; however, its use for the calculation of higher‐order parameters is limited by noise. We present an algorithm for denoising 4D‐flow data. Theory and Methods By integrating a velocity field and eliminating streamlines in noisy flow, depicted by high curvature, a denoised dataset may be extracted. This method, defined as the velocity field improvement (VFIT) algorithm, was validated in an analytical dataset and using in vivo data in comparison with a computation fluid dynamics (CFD) simulation. As a proof of principal, wall shear stress (WSS) measurements in the descending aorta were compared with those defined by CFD. Results The VFIT algorithm achieved a >100% noise reduction of a corrupted analytical dataset. In addition, 4D‐flow data were cleaned to show improved spatial resolution and near wall velocity representation. WSS measures compared well with CFD data and bulk flow dynamics were retained (