Characteristics of Lung Perfusion and Ventilation in Healthy Adults: A Prospective Study with Phase-resolved Functional Lung Magnetic Resonance Imaging

Background Lung prefusion and ventilation under physiological conditions have not been evaluated and visualized before. We aim to analyse pulmonary perfusion and ventilation between tidal and deep breathing in healthy individuals and compared differences between sexes and age groups with Phase-Resolved Functional Lung Magnetic Resonance Imaging (PREFUL- MRI). Methods This prospective observational study included healthy volunteers from May 2023 to May 2024. All participants underwent PREFUL-MRI in the supine position during tidal and deep-slow breathing using a balanced steady-state free-precession sequence. Perfusion-and ventilation-related metrics on PREFUL-MRI were analysed with an automated quantitative pipeline and compared between tidal and deep breathing, sexes and age groups. Results Eighty-seven healthy participants (47 men, mean age: 38.6 ± 12.3 years) were enrolled. Mean perfusion (7.7% vs. 6.0%, p < 0.001) and ventilation defects (8.6% vs. 5.1%, p = 0.002) were decreased, and mean ventilation (15.8% vs. 48.3%, p < 0.001) and perfusion defects (1.9% vs 7.9%, p = 0.001) increased during deep breathing compared with those during tidal breathing. Twenty-eight participants had increased lung perfusion while the other 59 people had reduced perfusion during tidal breathing. During tidal breathing, men exhibited higher mean ventilation (20.2% vs. 14.2%, p = 0.002) and more ventilation defects (9.5% vs. 6.3%, p = 0.022)than did women. Perfusion defects decreased in participants aged ≥ 45 years compared with those aged < 45 years (1.6% vs. 2.6%, p = 0.029). Mean flow-volume loop correlations were similar between tidal and deep breathing, sexes and age groups (p > 0.05). Conclusion PREFUL-MRI enables visually analysing lung perfusion and ventilation, thus enhancing our understanding of the physiological characteristics and alterations of lung.