Atlas of Brain Glucose Metabolism Using Deuterium Metabolic Imaging at 3 T

Deuterium metabolic imaging (DMI) offers noninvasive magnetic resonance imaging (MRI)-based assessment of metabolism in vivo, making it a relevant paraclinical tool for diseases with neurological metabolic alterations. This study aimed to establish a normative reference atlas of brain glucose metabolism accounting for age and sex.

DMI were obtained for 30 healthy adults (aged 51-84 years, 15 female) with a 3 T MRI scanner after ingestion of deuterated [6,6'-²H₂]glucose. The images were parcellated to determine the regional distribution of deuterated water, glucose, lactate, and glutamate plus glutamine (Glx). Linear models were applied to investigate the effects of age, sex, and other exploratory adjustments. As a proof-of-concept example of atlas application, the normative atlas was compared with patients with Alzheimer's disease and healthy subjects from a previous study.

Regional differences were significant for all metabolites (p < 10^-15), with the highest values in the occipital lobes, except for lactate, whose regional distribution pattern was less consistent. While lactate production showed no overall age-dependency, global Glx production decreased 13% ± 4% per decade. Lactate production tended to be higher in males than females (p = 0.042), but this was not significant after regional adjustment (p = 0.084). Discriminating between health and Alzheimer's disease required additional adjustments for weight, blood glucose, and timing.

While regional and age effects explained a substantial part of the variability in Glx, reliable intersubject comparisons required additional adjustments. The normative atlas presented here provides a reference for future DMI studies of brain metabolism.