Impact of Partial Echo on 4D Flow MRI: The Insight From Synthetic MRI

Abstract

Purpose: The aim of this study is to investigate the impact of the partial echo on 4D flow MRI sequences thanks to in silico coupled MRI-CFD (computational fluid dynamics) simulations.

Methods: Two sequences are studied: one with a full echo (FE) and another using partial echo (PE) with an echo symmetry fraction of 0.75. MRI-CFD simulations are conducted on an in silico pulsatile flow phantom for a sinusoidal inflow and a physiological inflow typical of the ascending aorta.

Results: For both inflow signals, PE-based simulations exhibited better compliance with their matching CFD simulations compared to the FE ones.

Conclusion: The reduction of flow misregistration artifacts achieved through the use of PE appears to be more beneficial than the drawback of incomplete k-space filling. The MRI-CFD framework presented in this study appears as a useful tool to investigate the design of MRI sequences and to stratify its different sources of errors.

Keywords: 4D flow; computational fluid dynamics (CFD); numerical simulation; partial echo (PE).