Dynamic lung water magnetic resonance imaging during exercise stress

Motivation: Quantification of lung water during exercise is of interest for early diagnosis of heart failure. Goal(s): To develop a time-resolved 3D MRI method to quantify lung water in transitions between rest and exercise. Approach: We derive quantitative time-resolved lung water density (LWD) maps using a motion corrected sliding-window image reconstruction. We included 12 healthy controls and 2 patients with heart failure, and a porcine model of mitral regurgitation (n=5). Results: We measured a peak exercise ΔLWD=16±6.8% in controls, but detected no changes during rest (ΔLWD=-1.4±3.5%, p=0.18). Accumulation rates were slower in patients (2.0±0.1%/min) vs controls (2.6±0.9%/min). Animals developed ΔLWD=3.3±1.5%. Impact: Exercise-induced changes in lung water can be dynamically quantified using a continuous 3D MRI acquisition with a sliding-window and motion corrected image reconstruction, which may have clinical utility in unmasking latent heart failure at early stages of disease.