Oxygen-enhanced MR ventilation imaging of the lung: Preliminary clinical experience in 25 subjects

Objective. The purpose of this study was to show the feasibility of oxygen- enhanced MR ventilation imaging in a clinical setting with correlation to s tandard pulmonary function tests, high-resolution CT, and Kr-81m ventilatio n scintigraphy. Subjects and methods. Seven healthy volunteers, 10 lung cancer patients, an d eight lung cancer patients with pulmonary emphysema were studied. A respi ratory synchronized inversion-recovery single-shot turbo-spin-echo sequence (TE, 16; inversion time, 720 msec; interecho spacing, 4 msec) was used for data acquisition. The following paradigm of oxygen inhalation was used: 21 % oxygen (room air), 100% oxygen, 21% oxygen. MR imaging data including max imum mean relative enhancement ratio and mean slope of relative enhancement were correlated with forced expiratory volume in 1 sec, diffusing lung cap acity, high-resolution CT emphysema score, and mean distribution ratio of K r-81m ventilation scintigraphy. Results. Oxygen-enhanced MR ventilation images were obtained in all subject s. Maximum mean relative enhancement ratio and mean slope of relative enhan cement of lung cancer patients were significantly decreased compared with t hose of the healthy volunteers (p<0.0001, p < 0.0001). The mean slope of re lative enhancement in lung cancer patients with pulmonary emphysema was sig nificantly lower than that of lung cancer patients without pulmonary emphys ema (p < 0.0001). Maximum mean relative enhancement ratio (r(2) = 0.81) was excellently correlated with diffusing lung capacity. Mean slope of relativ e enhancement (r(2) = 0.74) was strongly correlated with forced expiratory volume in 1 sec. Maximum mean relative enhancement had good correlation wit h the high-resolution CT emphysema score (r(2) = 0.38), The maximum mean re lative enhancement had a strong correlation with the distribution ratio (r( 2) = 0.77). Conclusion. Oxygen-enhanced MR ventilation imaging in human subjects showed regional changes in ventilation, thus reflecting regional lung function.