Longitudinal H-1 MRS changes in mild cognitive impairment and Alzheimer's disease

Magnetic resonance (MR)-based volume measurements of atrophy are potential markers of disease progression in patients with amnestic mild cognitive impairment (MCI) and Alzheimer's disease (AD). Longitudinal changes in H-1 MR spectroscopy (H-1 MRS) metabolite markers have not been characterized in MCI subjects. Our objective was to determine the longitudinal H-1 MRS metabolite changes in patients with MCI, and AD, and to compare H-1 MRS metabolite ratios and ventricular volumes in tracking clinical disease progression in AD. The neuronal integrity marker N-acetylaspartate/creatine ratio declined in MCI and AD patients compared to cognitively normal elderly. The change in H-1 MRS metabolite ratios correlated with clinical progression about as strongly as the rate of ventricular expansion, suggesting that H-1 MRS metabolite ratios may be useful markers for the progression of AD. Choline/creatine ratio declined in stable MCI, compared to converter MCI patients and cognitively normal elderly, which may be related to a compensatory mechanism in MCI patients who did not to progress to AD. (C) 2006 Elsevier Inc. All rights reserved.