A Variability Study of Regional Alveolar Oxygen Tension Measurement in Humans Using Hyperpolarized 3He MRI

摘要

To presents the first systematic reproducibility measurement of alveolar partial pressure of oxygen (pAO2) in the human lung, regional variability is defined in terms of an intraclass correlation coefficient (ICC) between co-localized, same-subject measurements separated by one-week or couple of minutes (short-term). In addition, the repeatability of the average lung pAO2 is compared to that of the standard pulmonary function tests (PFT).PFT and pAO2 imaging were performed on eight subjects: 4 nonsmokers (1 man, 3 women; 56 ± 1.7 years), 4 smokers (1 woman, 3 men; 52 ± 7.5 years) in three visits during two weeks. Regional variability was assessed based on a mixed-effects model and an ICC. The coefficient of variation (CV) of mean and standard deviation of pAO2 in three days was also compared to CV of PFT results.Short-term regional reproducibility based on ICC was 0.71 and 0.63 for nonsmokers and smokers; respectively. The one-week variability was lower (ICC=0.59 and 0.47; respectively). The CV of whole-lung average pAO2 was significantly higher than that of FVC(forced vital capacity; P=0.02) but not from DLCO (diffusing capacity).The smoker group shows more variability in pAO2 measurements both between experiments and in each individual pAO2 maps. pAO2 had a similar repeatability to DLCO.