OBJECTIVES: To prospectively estimate the feasibility and reproducibility of dynamic @entity26 -enhanced magnetic resonance imaging (OE-MRI) in the assessment of regional @entity26 delivery, uptake and washout in @entity748 lungs. MATERIALS AND METHODS: The study was approved by the National Research Ethics Committee and written informed consent was obtained. Dynamic OE-MRI was performed twice at one month apart on four mild @entity748 @entity1 (23  5 years old, FEV1=96  3% of predicted value) and six severe @entity748 @entity1 (41  12 years old, FEV1=60  14% of predicted value) on a 1.5T MR scanner using a two-dimensional T1-weighted inversion-recovery turbo spin echo sequence. The enhancing fraction (EF), the maximal change in the partial pressure of @entity26 in lung tissue (  PO2max_l) and arterial blood of the aorta (  PO2max_a), and the @entity26 wash-in (  up_l,   up_a) and wash-out (  down_l,   down_a) time constants were extracted and compared between groups using the independent-samples t-test (two-tailed). Correlations between imaging readouts and clinical measurements were assessed by Pearson's correlation analysis. Bland-Altman analysis was used to estimate the levels of agreement between the repeat scans and the intra-observer agreement in the MR imaging readouts. RESULTS: The severe @entity748 group had significantly smaller EF (70  16%) and median   PO2max_l (156  52mmHg) and significantly larger interquartile range of   up_l (0.84  0.26min) than the mild @entity748 group (95  3%, P=0.014; 281  40mmHg, P=0.004; 0.20  0.07min, P=0.001, respectively). EF, median   PO2max_l and   down_l and the interquartile range of   up_l and   down_l were significantly correlated with age and pulmonary function test parameters (r=-0.734 to -0.927, 0.676-0.905; P=0.001-0.045). Median   PO2max_l was significantly correlated with   PO2max_a (r=0.745, P=0.013). Imaging readouts showed good one-month reproducibility and good intra-observer agreement (mean bias between repeated scans and between two observations did not significantly deviate from zero). CONCLUSIONS: Dynamic OE-MRI is feasible in @entity565 and sensitive to the severity of disease. The technique provides indices related to regional @entity26 delivery, uptake and washout that show good one month reproducibility and intra-observer agreement.

Dynamic @entity26 -enhanced magnetic resonance imaging of the lung in XXXX -Initial experience.

@entity748 :: ('MESH:D013224', 'Disease') :: ['asthmatic'] @entity1 :: ('9606', 'Species') :: ['patients'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity565 :: ('MESH:D001249', 'Disease') :: ['asthma']
@entity565 :: (MESH:D001249,Disease) :: ['asthma']
