2. IPF patients diagnosed essentially according to the American Thoracic and European Respiratory Societies (ATS-ERS) by clinical diagnostic criteria of: (a) High-resolution computed tomography (HRCT) demonstrating a pattern of "confident" or "possible" IPF (b) Abnormal pulmonary physiology with evidence of restriction and/or impaired gas exchange (can exist during exercise alone) (c) Exclusion of other known causes of interstitial lung disease (e.g.: connective tissue disease, environmental exposure,etc.)[31].