Investigation of cardiac-rhythm related differences in hemodynamics using a 3D universal left atrial coordinate system dedicated to 4D Flow MRI

Motivation: 4D Flow MRI offers valuable hemodynamic information in individual subjects. Yet, understanding the hemodynamic involvement in atrial fibrillation (AF) requires inter-subject comparisons that are difficult due to the high variability and complex morphology of the left atrium (LA). Goal(s): Construct a 3D universal left atrial coordinate system (3D-ULAC) dedicated to 4D Flow MRI and use it to explore cardiac-rhythm related differences in LA hemodynamics. Approach: Paroxysmal AF and age-matched healthy subjects underwent 4D Flow MRI. LA hemodynamic parameters of each subject were transported to the same target 3D-ULAC for inter-group comparison. Results: Qualitatively different flow patterns were observed on group average hemodynamic maps. Impact: The volumetric universal coordinate system for the left atrium enabled straightforward comparisons of blood flow parameters between subjects. The method may prove valuable in larger populations studies to highlight pathology specific flow patterns and identify individuals with significantly different patterns.