Abstract: | This paper describes imaging of lung function with oxygen-enhanced MRI using dynamically acquired T 1 parameter maps, which allows an accurate, quantitative assessment of time constants of T 1-enhancement and therefore lung function. Eight healthy volunteers were examined on a 1.5-T whole-body scanner. Lung T 1-maps based on an IR Snapshot FLASH technique (TE = 1.4 ms, TR = 3.5 ms, FA = 7 ∘) were dynamically acquired from each subject. Without waiting for full relaxation between subsequent acquisition of T 1-maps, one T 1-map was acquired every 6.7 s. For comparison, all subjects underwent a standard pulmonary function test (PFT). Oxygen wash-in and wash-out time course curves of T 1 relaxation rate (R 1)-enhancement were obtained and time constants of oxygen wash-in (w in) and wash-out (w out) were calculated. Averaged over the whole right lung, the mean w out was 43.90 ± 10.47 s and the mean (w in) was 51.20 ± 15.53 s, thus about 17% higher in magnitude. Wash-in time constants correlated strongly with forced expired volume in one second in percentage of the vital capacity (FEV1 % VC) and with maximum expiratory flow at 25% vital capacity (MEF25), whereas wash-out time constants showed only weak correlation. Using oxygen-enhanced rapid dynamic acquisition of T 1-maps, time course curves of R 1-enhancement can be obtained. With w in and w out two new parameters for assessing lung function are available. Therefore, the proposed method has the potential to provide regional information of pulmonary function in various lung diseases. |