PULMONARY MYCOBACTERIAL INFECTIONS IN AIDS - CHARACTERISTIC PATTERN OF THALLIUM AND GALLIUM SCAN MISMATCH

PURPOSE: To evaluate the diagnostic specificity of thallium and galliu m scan mismatch as a sign of mycobacterial infection in immunodeficien t patients. MATERIALS AND METHODS: Thallium and gallium scans obtained in 56 immunodeficient patients between January 1989 and March 1994 we re retrospectively reviewed, with special attention to the final diagn oses in all patients with thallium-gallium scan mismatch compared with those whose scans showed other scintigraphic patterns. RESULTS: Fourt een patients had focal gallium uptake, but no thallium uptake, in the mediastinum and hilar nodes (thallium-gallium mismatch). Twelve of the 14 had culture-proved mycobacterial infections; one had cryptococcal infection; and in one, the diagnosis was not established. Thirty-seven of the remaining 42 patients who had different scintigraphic patterns on thallium-gallium scans had other complications of acquired immunod eficiency syndrome such as Kaposi sarcoma, non-Hodgkin lymphoma, and b acterial pneumonia. The diagnosis in five of the 42 patients was not k nown because follow-up data were incomplete. CONCLUSION: The thallium- gallium mismatch pattern in immunodeficient patients is specific for m ycobacterial infection.