| Tour 1: Next/Previous/Start: These images show typical findings in AIDS dementia: patchy hypoperfusion with a multifocal distribution which tends to be seen prominently in the frontal lobes. Compare with normal.
Defects in cerebral perfusion have been previously reported in HIV positive individuals by single photon emission computed tomography (SPECT)[Masdeu, 1989 ][Pascal, 1991 ][Pohl, 1988 ][Holman, 1992 ][Schielke, 1990]. The anatomic and clinical significance of these findings, however, has remained uncertain. Because previous studies have shown that AIDS dementia complex (ADC) is associated with both functional defects and structural evidence of brain volume loss, we spatially matched (registered) the functional and structural data to assess the extent to which observed perfusion defects were "real", that is, represented low tracer uptake from structurally normal brain. The image datasets shown here are sampled along the same plane of view, to permit the direct comparison of SPECT and MR images in ADC. This type of analysis shows that there are functional defects (ie perfusion defects) in areas that appear non-atrophic. These are perhaps sites of early damage in which
the structural images are still relatively normal.
|
|
