SUBCORTICAL WHITE-GREY MATTER CONTRAST ON MRI AS A QUANTITATIVE MARKER OF DIFFUSE HIV-RELATED PARENCHYMAL ABNORMALITY

White matter change occurs in human immunodeficiency virus (HIV) encep halopathy, which may be difficult to assess subjectively especially in the early stages of disease. This study applies a quantitative approa ch to the assessment of this finding. Sixty-three HIV seropositive sub jects, 47 seronegative blood donors and 17 seronegative homosexual men underwent axial T2 weighted MRI of the brain at 1.5T. Quantitative an alysis was performed by obtaining the pixel contrast between parieto-o ccipital white matter and head of caudate grey matter (C-wg), Highest values of C-wg were found in a subgroup of subjects with AIDS who had diffuse/patchy white matter abnormalities and atrophy on qualitative i mage assessment. Statistically significant differences were found in C -wg between subjects with high(greater than or equal to,200 x 10(6)/l) and low (<200 x 10(6)/l) CD4 lymphocyte counts (P < 0.05) and between subjects with and without HIV-1 associated cognitive/motor complex (P < 0.05). This technique provides an objective measure of diffuse HIV- related parenchymal abnormality seen on T2 weighted MRI.