Glucose utilization rate versus brain size in humans

Abstract

Cerebral glucose metabolic rates were measured in 23 normal volunteers by studying the uptake of ¹⁸F-deoxyglucose with positron emission tomography (PET). These values were correlated against a brain-size index obtained from the PET images by measuring the lateral and anteroposterior brain diameters. There was a significant negative correlation (p < 0.001), which corresponds, within the statistical uncertainty, to an inverse proportionality of glucose metabolic rate and brain volume. The variation with brain size accounted for approximately one-half of the total intersubject variance. Measurements on phantoms of different sizes and analyses of instrumental errors failed to uncover any artifactual reason for the correlation.