The comparison of quantitative CT features of COPD and pre-COPD: results from a reallife study

Background: Although fixed airway obstruction on spirometry is crucial for COPD diagnosis, it might be insufficient to identify subjects with pre-COPD. Quantitative computerized tomography (CT) measurements might be helpful to distinguish the subjects with pre-COPD. Thus, we aimed to compare quantitative CT findings of subjects with pre-COPD and COPD. Methods: Subjects who were admitted to our clinic with chronic respiratory symptoms and were evaluated for COPD as a pre-diagnosis were included in the study. Subjects were categorized as COPD and pre-COPD groups according to the FEV1/FVC ratio. Thorax CT voxel-based attenuation analysis was performed by Myrian® Expert software(Intrasense SA-1231, Montpellier, France). Attenuation values lower than -950 Hounsfield Units (HU) were defined as emphysema. Results: Of 163, 106 COPD and 57 pre-COPD cases were included. COPD group had significantly higher lung volume (5683 ml vs 4921 ml, p=0.001) and lower mean attenuation value (-830.0 HU vs -808.2 HU, p<0.001) than the pre-COPD group. Moreover, the COPD group had a higher emphysema percentage than the pre-COPD group (3.87% vs 0.28%, p<0.001). Conclusion: Quantitative CT of pre-COPD demonstrated radiologic findings that might help to corroborate COPD diagnosis, which was also associated with the severity of the airflow obstruction and be an alternative method for COPD diagnosis when it is difficult to reach spirometry.