Repeatability and cross field strength reproducibility of lung water MRI at rest and exercise stress

Motivation: Our recently developed MRI method to measure transient lung water during exercise stress has potential value in the evaluation of heart failure, but its repeatability and reproducibility has not yet been assessed. Goal(s): To assess the test-retest repeatability and 0.55T-1.5T field strength reproducibility of lung water MRI at rest and exercise. Approach: We included n=10 healthy subjects who underwent two lung MRI exams within three days, at 0.55T and 1.5T. Each exam included two lung water images at rest, and two during exercise. Results: Lung water densities were repeatable at rest and exercise at both field strengths. Quantitative values were lower at 1.5T. Impact: Dynamic lung water MRI during exercise stress may have clinical utility in heart failure. Understanding this method's repeatability and performance across different magnetic field strengths accelerates the clinical adoption of this tool.