Noise and background phase correction in 4D flow CMR: effects on aortic flow, hemodynamic forces and kinetic energy

Motivation: Measures on 4D flow are attracting increasing clinical attention as sensitive markers of cardiac function. The accuracy and precision of 4D-flow CMR is subject to residual phase offsets, which are commonly mitigated using offline postprocessing, and image noise. Goal(s): The aim of this study was to evaluate how noise and phase background correction strategies impact 4D-flow analysis. Approach: Aortic flow and left ventricular hemodynamic forces and kinetic energy were analyzed with varying levels of noise and different phase background correction strategies. Results: Hemodynamic-force analysis is insensitive to background correction strategy and random noise. In contrast, kinetic energy is significantly affected by noise. Impact: Hemodynamic forces are insensitive to background correction strategy and noise. In contrast, kinetic energy is significantly affected by noise levels seen in clinical scans. Hemodynamic force analysis therefore holds promise as a robust clinical measure of cardiac function.