[Aerosol pulmonary scintigraphy. A new test in the diagnostic strategy of pneumocystis carinii pneumonia in patients with acquired immunodeficiency syndrome].

In eleven patients with AIDS and suspected Pneumocystis carinii pneumonia we measured the pulmonary clearance and half-life of aerosolized 99m Tc-DTPA (diethylenetriamine pentaacetate). We correlated the half-life with gallium scans and bronchoalveolar lavages. In all nine patients with Pneumocystis, this half-life was shorter than normal value, documenting a significant increase of lung epithelial permeability (p less than 0.001). Six of these 9 patients had abnormal gallium scans. However, in two patients with normal chest X-rays, PaO2 and gallium scans, only the reduced half-life of 99mTc-DTPA evidenced acute lung disease. After treatment, the results of the DTPA half-life correlated with the presence or absence of Pneumocystis. This method is, therefore, a sensitive initial diagnostic test in patients with suspected Pneumocystis pneumonia. A short half-life should prompt bronchoalveolar lavage even when PaO2 and/or chest X-rays and gallium scans are normal.