Technetium-99m-DTPA aerosol and gallium-67 scanning in pulmonary complications of human immunodeficiency virus infection.

We retrospectively compared the results of 67Ga chest scans and 99mTc-DTPA aerosol clearance measurements with those of fiberoptic bronchoscopy in 88 patients infected with the human immunodeficiency virus. Of 100 investigations, a pulmonary infection was diagnosed in 39, mainly Pneumocystis carinii pneumonia and a noninfectious disorder was found in 42, mainly Kaposi's sarcoma and lymphocytic alveolitis. Gallium scans and DTPA clearance were abnormal respectively in 74% and 92% of infectious complications, and in 12% and 60% of noninfectious disorders. In 10 cases, DTPA clearance was accelerated, while chest x-ray, arterial blood gases and even gallium scanning were normal. A value of DTPA clearance greater than 4.5%.min-1 was both sensitive and specific for the diagnosis of Pneumocystis carinii pneumonia. The gallium scan was always normal in bronchopulmonary Kaposi's sarcoma. We conclude that in symptomatic patients: (1) DTPA clearance measurements are useful for detecting lung disease when chest x-ray and/or PaO2 are normal and (2) a gallium scan is indicated to distinguish progressive Kaposi's sarcoma from a superimposed second process when radiological abnormalities of pulmonary Kaposi's sarcoma are present.