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.

The use of lung ultrasound (LUS) is instrumental in the evaluation of many thoracic diseases and its ability to detect pleural-pulmonary pathologies is widely accepted. However, the use of LUS as an indication of underlying parenchymal lung disease, when the organ is still aerated, is a relatively new application. A-lines and B-lines are two separate and distinct artifacts which may be seen during the examination of the nonconsolidated lungs by ultrasound because of different underlying structures. Even though the practical role of LUS artifacts is accepted for detecting and monitoring many conditions, we do not fully understand their origin. The artifactual information beyond the pleura line in LUS images of the normal and of the not critically deflated lung represents the ultimate outcome of complex interactions of a specific acoustic wave with a specific three-dimensional structure of the biological tissue.

Chronic obstructive pulmonary disease (COPD) is a complex condition with a wide spectrum of clinical presentations and pathological features unified under the spirometric definition of airflow obstruction. The mechanisms responsible for airflow obstruction in COPD (airway narrowing and parenchymal destruction) cannot be distinguished by standard spirometry.

Chest computed tomography (CT) allows to depict and measure in vivo the lung pathologic changes of COPD by quantifying parenchymal destruction, the direct sign of emphysema. Although quantitative and qualitative studies have shown that CT can allow distinguishing subtypes of emphysema, a widespread routine use of CT for the assessment of COPD in clinical practice cannot be currently foreseen due to radiation exposure and limited instrumental availability.

LUS can detect pleural-pulmonary pathologies. However, the use of LUS as an indication of underlying parenchymal lung disease, when the organ is still aerated, as in emphysema, is a new application.

This study is aimed at researching correlations among a pool of data deriving from ultrasonographic and tomographic evaluations of patients with panlobular or paraseptal emphysema, to improve the comprehension of acoustic information derived from ultrasound evaluation.

The study will not modify the diagnostic / therapeutic process of the enrolled patients, who will all have in common the CT evidence of panlobular or paraseptal emphysema.

Researchers will observe three defined population of patients at a single point (at the time of enrolment). All subjects will have CT evidence of panlobular or paraseptal emphysema. Patients will be recruited through three paths: 1) patients suffered from COPD, in follow-up at Pulmonary Medicine Units in Rome and Naples, with HRCT evidence of paraseptal or panlobular emphysema; 2) subjects who participate in the screening program for lung cancer in Rome, Naples and Acquaviva delle Fonti, and 3) patients with suspected/known lung cancer managed in all medical Units involved in this project.

All enrolled subjects 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 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. IOS is almost independent of patient cooperation and can test a larger patient range than spirometry alone including geriatric patients.

Inclusion Criteria:

• outpatients in follow-up for chronic obstructive pulmonary disease, in stable conditions, with computed tomographic evidence of panlobular or paraseptal emphysema.
• Inpatients, admitted to the hospital due to acute exacerbation of chronic obstructive pulmonary disease, with computed tomographic evidence of panlobular or paraseptal emphysema.
• Subjects who participate in the screening program for lung cancer with computed tomographic evidence of panlobular or paraseptal emphysema.
• Outpatients / Inpatients with suspected/known lung cancer and computed tomographic evidence of panlobular or paraseptal emphysema.
• Patients able to give written informed consent.

Exclusion Criteria:

• pregnancy.
• Pediatric population.
• Patients unable to express written informed consent.

Researchers intend to communicate the trial results to participants, healthcare professionals, and other relevant groups through scientific publications and national and international conference proceedings. No individual participant data will be available.

Any document produced, including scientific publications relating to the research project will contain an explicit indication that the project is financed under the PNRR statement stating "funded by the European Union - Next Generation EU - PNRR M6C2 - Investment 2.1 Enhancement and strengthening of biomedical research in the NHS", the emblem of the Union European Union and the project code. The products will be made public through systems that allow immediate use by the public (for example open-access).