Radiologic findings in interstitial pulmonary emphysema

Nine patients with pneumomediastinum ranging in age from 0 to 72 years were reviewed. X-ray CT (“ReView” or high resolution CT) showed interstitial pulmonary emphysema (IPE) in perivascular and peribronchial space in 2 of the patients. IPE has been widely recognized as a cause of pneumomediastinum. Plain chest radiography did not demonstrate IPE because of the superimposition of pneumomediatinum, subctaneous emphysema, and lucency of the lung. Nevertheless, X-ray CT was useful for the diagnosis of patients in the intensive care unit. Recognition of IPE is important because it may directly impair pulmonary ventilation and may be followed by the development of pneumomediastinum or secondary infection.