The goal of this clinical trial is to identify correlations among data deriving from lung ultrasonographic (LUS) and tomographic evaluations of patients with panlobular or paraseptal emphysema, to improve the comprehension of acoustic information derived from ultrasound evaluation. The main question it aims to answer is: what are the correlations between thoracic ultrasonographic patterns and peripheral parenchymal changes evaluated by high resolution computed tomography (HRCT) of the chest, in patients affected with variable degree of panlobular or paraseptal emphysema? Researchers will compare LUS patterns observed in: 1) COPD patients with CT evidence of panlobular or paraseptal emphysema, 2) subjects participating in the screening program for lung cancer with CT evidence of panlobular or paraseptal emphysema, and 3) patients with suspected/known lung cancer undergoing with CT evidence of panlobular or paraseptal emphysema, with the ones obtained from healthy volunteers and subjects who participate in the screening program for lung cancer with no evidence of emphysema. Participants will undergo LUS evaluation with both clinical and research scanners. Patients will be assessed in supine position with the arms extended above the head. The position is the same in which chest CT scans will be performed. LUS assessment will be performed using commercially available linear probes. Finally, all COPD patients and subjects who participate in the screening program for lung cancer with CT evidence of paraseptal or panlobular emphysema will undergo respiratory oscillometry. Tidal breathing analysis with impulse oscillometry (IOS) has proven to be an informative and meaningful tool used in the early detection and follow up of pulmonary diseases like COPD.