H-1 AND P-31 MAGNETIC-RESONANCE SPECTROSCOPIC IMAGING OF WHITE-MATTERSIGNAL HYPERINTENSITY AREAS IN ELDERLY SUBJECTS

White matter signal hyperintensities (WMSH) are commonly seen on MRI o f elderly subjects. The purpose of this study was to characterize meta bolic changes in the white matter of elderly subjects with extensive W MSH. We used water-suppressed proton (H-1) magnetic resonance spectros copic imag ing (MRSI) to compare six subjects with extensive WMSH with eight age-matched elderly subjects with minimal or absent WMSH, and p hosphorus ((31)p) MRSI to compare nine subjects with extensive WMSH an d seven age-matched elderly subjects without extensive WMSH. Relative to region-matched tissue in elderly controls, extensive WMSH were asso ciated with increased signal from choline-containing metabolites, no s ignificant change of signal from N-acetylaspartate, and a trend to a d ecreased phosphomonoester (PME) resonance. These findings suggest that WMSH may be associated with an alteration of brain my elin phospholip ids in the absence of axonal damage. There were no differences in ener gy phosphates, consistent with lack of ongoing brain ischemia. Within the group with extensive WMSH, PME resonance measures were significant ly lower in WMSH than in contralateral nor mal-appearing white matter. These results provide information on pathophysiology of WMSH and a ba sis for comparison with WMSH in Alzheimer's disease, vascular dementia , multiple sclerosis, and other diseases.