Detection and Characterization of Pulmonary Disease by Transthoracic Doppler (TTD)

Inclusion Criteria: * Able and willing to provide informed consent * Age 18 years or older * Clinic and hospital records including additional background medical data such as results of echocardiograms, cardiac catheterization pathology reports etc., available and accessible. * Evaluation by a physician who determines that a High Resolution Computed Tomography (HRCT) of the Thorax and pulmonary function tests, including spirometry, lung volumes and diffusion capacity, are indicated as part of the standard clinical care. * If full lung function tests are normal imaging with a regular chest x-ray is sufficient. * Study Population - subjects will be grouped based on the following criteria after obtaining pulmonary function tests and HRCT of the thorax - 1. COPD based on clinical assessment and spirometry showing airflow limitation i.e., (FEV1/FVC \< 0.70). 2. Interstitial lung disease (ILD) diagnosed by HRCT. 3. Control subjects presenting with pulmonary complaints evaluated by full PFTs (spirometry, lung volume and DLCO) and a chest x-ray and/or HRCT , all found to be within normal limits, . Exclusion Criteria: * Primary or metastatic lung cancer. * Acute pneumonia. * Concomitant or previous diagnosis of Bronchial Asthma. * Patients with severe chest wall deformity * Decompensated heart failure or volume overload. * Significant right-sided pleural effusion.