Usefulness of quantitative computed tomography analysis using a commercially available software program through its simple and automatic procedures in evaluation of emphysema and pulmonary fibrosis

Abstract

BackgroundThe aim of this study was to investigate the usefulness of quantitative computed tomography (CT) analysis using a commercially available software program through its simple and automatic procedures. The software program, which was developed with the density mask technique using two thresholds, was used for simultaneously assessing both the low attenuation volume (LAV) and high attenuation volume (HAV) to detect emphysema and pulmonary fibrosis.MethodsIn this prospective cohort study of stable patients with chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), we investigated the correlations between quantitative assessments performed using the software program and visual assessments, and between pulmonary function parameters and quantitative assessment parameters. We also investigated whether the utility of quantitative assessments could improve by assessing the destroyed lung volume (DLV), defined as the LAV+HAV.ResultsStrong significant correlations were detected between the percentage of LAV (LAV%) and the visual assessment of emphysema and between the percentage of HAV (HAV%) and the visual assessment of pulmonary fibrosis. A receiver operating characteristic curve analysis revealed 86.8% sensitivity and 84.2% specificity for the LAV% to detect emphysema, using 1.5% as the cut-off value, and 87.5% sensitivity and 96.1% specificity for the HAV% to detect pulmonary fibrosis, using 12% as the cut-off value. The percentage of DLV (DLV%) significantly correlated with the diffusion capacity of lung for carbon monoxide (DLco) and delta N2 in patients with COPD. Meanwhile, the DLV% significantly correlated with DLco and the composite physiologic index in patients with IPF. Moreover, the DLV% significantly also correlated with DLco in total patients with COPD and IPF.ConclusionsThe quantitative CT analysis using a commercially available software program could be useful in clinical practice by the advantage of the simple and automatic procedures. The utility of the quantitative CT analysis could improve by assessing the DLV%.