H-1 MR spectroscopic imaging of white matter signal hyperintensities: Alzheimer disease and ischemic vascular dementia.

Purpose: To investigate the association of white matter signal hyperintensities (WMSHs) with changes in hydrogen-1 metabolites.
Materials and Methods: T2-weighted magnetic resonance (MR) imaging and H-1 MR spectroscopic imaging were performed in 21 elderly control subjects without or with minimal WMSHs, eight elderly subjects with substantial WMSHs, 11 probable Alzheimer disease patients with WMSHs, and eight ischemic vascular dementia (IVD) patients with WMSHs. N-acetylaspartate (NAA), choline-containing metabolites (Cho), and creatine-containing metabolites (Cr) were analyzed.
Results: Differences in regional metabolite levels were found within the supraventricular brain of elderly control subjects. In Alzheimer disease patients, extensive WMSHs showed a lower percentage of NAA and a higher percentage of Cho compared with contralateral normal-appearing white matter (NAWM); in IVD patients, extensive and large WMSHs were associated with a higher percentage of Cho and a lower percentage of Cr compared with contralateral NAWM.
Conclusion: Regional metabolite variation and the presence of WMSHs are important covariants that must be accounted for in analysis of MR spectroscopic data.