Diagnostic uses of nuclear medicine in AIDS

Radionuclide imaging, if applied with an organ system approach, is useful in the diagnosis of the AIDS (acquired immunodeficiency syndrome)-related complex. Specific pathologic processes can be suspected on the basis of uptake patterns. The intensity and pattern of pulmonary uptake and concomitant nonpulmonary uptake of gallium provide guidelines for distinguishing among various opportunistic pulmonary pathogens. Gastrointestinal and extra-gastrointestinal tract uptake of gallium aids distinction among fungal, mycobacterial, and viral infections and neoplasms. Patterns of spleen uptake of technetium-99m sulfur colloid and gallium allow differentiation between neoplasm (Kaposi sarcoma) and infection (with mycobacteria). Skeletal and soft-tissue abnormalities can be characterized and differentiated on the basis of bone scan and other radionuclide scan findings. Thallium uptake in brain tumors (and not in areas of infection) allows brain lesion discrimination. In the proper clinical setting, AIDS nephropathy has a characteristic gallium uptake pattern. Cardiac abnormalities (including functional) can also be assessed with scintigraphy. With knowledge of these organ-specific patterns and with correlative imaging studies, the manifestations of AIDS can be differentiated and appropriate treatment instituted.