This paper reviews currently available PET studies performed either to improve our understanding of the pathogenesis of HIV-1
infection or to assess the value of PET imaging in the clinical decision making of patients infected with HIV-1 presenting with
AIDS-related opportunistic infections and
malignancies. FDG PET has shown that HIV-1
infection progresses by distinct anatomical steps, with involvement of the upper torso preceding involvement of the lower part of the torso, and that the degree of FDG uptake relates to viral load. The former finding suggests that lymphoid tissues are engaged in a predictable sequence and that diffusible mediators of activation might be important targets for
vaccine or therapeutic intervention strategies. In lipodystrophic HIV-infected patients, limited available data support the hypothesis that
stavudine-related
lipodystrophy is associated with increased
glucose uptake by adipose tissue as a result of the metabolic stress of adipose tissue in response to highly active antiretroviral treatment (
HAART). Finally, in early
AIDS-related dementia complex (ADC), striatal hypermetabolism is observed, whereas progressive ADC is characterized by a decrease in subcortical and cortical metabolism. In the clinical setting, PET has been shown to allow the differentiation of
AIDS-related opportunistic infections and
malignancies, and to allow monitoring of side effects of
HAART. However, in patients suffering from
HIV infection and presenting with extracerebral
lymphoma or other human
malignancies, knowledge of viraemia is essential when interpreting FDG PET imaging.