Objective: Brain glucose hypometabolism is a prominent feature of Alzheimer's disease (AD), and in this case-control study we used Magnetic Resonance Spectroscopy (MRS) to assess AD-related differences in the posterior cingulate/precuneal ratio of glucose, lactate, and other metabolites.
Methods: J-modulated Point-Resolved Spectroscopy (J-PRESS) and Prior-Knowledge Fitting (ProFit) software was used to measure glucose and other metabolites in the posterior cingulate/precuneus of 25 AD, 27 older controls, and 27 younger control participants. Clinical assessments for AD participants included cognitive performance measures, insulin resistance metrics and CSF biomarkers.
Results: AD participants showed substantially elevated glucose, lactate, and ascorbate levels compared to older (and younger) controls. In addition, the precuneal glucose elevation discriminated well between AD participants and older controls. Myo-inositol correlated with CSF p-Tau181P, total Tau, and the Clinical Dementia Rating (CDR) sum-of-boxes score within the AD group.
Interpretation: Higher glucose to creatine ratios in the AD brain likely reflect lower glucose utilization. Our findings reveal pronounced metabolic abnormalities in the AD brain and strongly suggest that brain glucose merits further investigation as a candidate AD biomarker.