Lung Diffusing Capacities Normality Thresholds in Pulmonary Fibrosis and Emphysema

The investigators tested the usefulness of lung diffusing capacities for carbon monoxide (DLco) and nitric oxide (DLNO) normality thresholds of 5th and 2.5th percentiles for the assessment of intersitial pulmonary fibrosis (IPF) and pulmonary emphysema (PE). Computed tomography (CT) of the chest was taken as a gold standard for the presence of lung parenchymal abnormalities typical of these conditions. The investigators retrospectively utilized the DLco and DLNO data obtained by a single device in sixty-six subjects with IPF included in two previous studies and in fifty-four new subjects with PE, both documented by quantitative CT of the chest.