Analysis of Pulsatile Vessel Expansion in Healthy, COPD ‐and PH ‐Patients Using Dynamic Vessel Segmentation in Free‐Breathing Lung MRI

ABSTRACT Background The pulsatile expansion of pulmonary vessels carries dynamic cardiopulmonary information that may reveal disease earlier than structural changes alone. Purpose To test (i) intra‐ and inter‐scan repeatability of dynamic vessel metrics in healthy subjects, and (ii) whether chronic obstructive pulmonary disease (COPD) and postcapillary pulmonary hypertension (PH) exhibit disease‐specific differences. Study Type Retrospective, multi‐cohort feasibility study with repeatability sub‐study. Subjects Healthy: 29 (11 female), COPD: 52 (15 female), PH: 25 (15 female) with isolated postcapillary PH. Fieldstrength/Sequence 1.5T, free‐breathing spoiled gradient‐echo sequence, TE = 0.82 ms, TR = 3 ms, flip angle = 5°. Assessment 2D U‐Nets segmented pulmonary vessels throughout each series of 250 images. Dynamic metrics included the coefficient of variation (CV) of vessel area and CV of vessel signal. Delay between vessel signal and vessel expansion as %‐of‐RR‐interval (SE‐delay) together with the heart rate and lung area were calculated. Statistical Tests Repeatability: Friedman; intraclass correlation coefficient (ICC); standard error of measurement (SEM) and the minimal detectable change (MDC). Group comparisons: Kruskal–Wallis and multiple linear regression. p 0.391; p > 0.069). Data Conclusion Free‐breathing lung MRI with automated vessel segmentation reveals distinct hemodynamic characteristics in COPD and PH. This method shows potential as a sensitive non‐invasive tool for detection, phenotyping, and treatment monitoring in pulmonary pathology. Evidence Level 3. Technical Efficacy 2.