3D Dynamic Oxygen-Enhanced Pulmonary Magnetic Resonance Imaging Based on Free-Breathing UTE

Lung function can be investigated by OE-MRI via alternation between room air and pureoxygen during a dynamic ventilation process, where oxygen wash-in time has been reported to relate to var-ious diseases. This pilot study investigates the feasibility of a free-breathing 3D dynamic oxygen-enhancedMRI (OE-MRI) technique using a golden-angle stack-of-stars ultra-short echo time (UTE) sequence withsliding-window reconstruction for whole-lung functional assessment. The continuous acquisition model wasused to capture both steady states and the gas-switching process. Images along the time dimension werereconstructed using the sliding window technique. Comparative analysis with the traditional IR-HASTEsequence revealed significantly longer wash-in times (55.8 ± 17.4 s, 70.1 ± 19.0 s, 58.1 ± 17.9 s, 89.0 ±21.7 s and 79.5 ± 18.7 s) with the UTE-based approach, which may reflect either enhanced sensitivityto oxygen delivery dynamics or potential confounding effects from the sliding-window reconstruction’stemporal smoothing. The Wilcoxon signed-rank test did not reveal a statistically significant differencebetween the measurements obtained from the UTE and IR-HASTE sequences (p = 0.062 and 0.063). Despitethis methodological consideration, the regional distribution of wash-in times showed reasonable agreementwith percent signal enhancement maps, supporting the technique’s feasibility. Compared to IR-HASTEmethod which needs breath-hold or respiratory gate, the proposed method can be performed during free-breathing. While promising as a technical framework for 3D dynamic lung imaging, the study highlightsimportant considerations regarding reconstruction algorithms in quantitative OE-MRI. Future work shouldfocus on validating these findings in patient populations and exploring alternative reconstruction strategiesto better characterize the method’s clinical potential for assessing pulmonary function.