THE IMAGING OF HIV-RELATED BRAIN DISEASE

Advanced HIV disease is strongly associated with an increased occurrence of various neuropsychiatric disorders,(1) and highly active antiretroviral therapy (HAART) is an important aspect of managing these conditions effectively.(2) In addition, there is growing recognition that many HIV-infected individuals will develop neuropsychiatric disorders relatively early in the course of HIV disease, in many cases before CD4 cell counts drop below 500 cells/mu l.(3) However, it is not known who in the earlier phases of the disease will go on to develop neurocognitive disorders, or who will respond to treatment.(4,5) New approaches in neuro-imaging have the potential to detect early HIV-associated damage in the brain. Preliminary evidence suggests that the neurotoxic effects of HIV result in damage to white matter tracts in the brain.(6) Once damage is established and related cognitive disorders ensue, the ability of HAART to reverse existing dysfunction is probably limited.(7) Earlier treatment with HAART in at-risk or minimally symptomatic patients may prevent further decline in cognition and delay the course of HIV disease.