Impact of Global Mean Normalization on Regional Glucose Metabolism in the Human Brain.

Impact of Global Mean Normalization on Regional Glucose Metabolism in the Human Brain. Neural Plast. 2018;2018:6120925 Authors: Mortensen KN, Gjedde A, Thompson GJ, Herman P, Parent MJ, Rothman DL, Kupers R, Ptito M, Stender J, Laureys S, Riedl V, Alkire MT, Hyder F Abstract Because the human brain consumes a disproportionate fraction of the resting body's energy, positron emission tomography (PET) measurements of absolute glucose metabolism (CMRglc) can serve as disease biomarkers. Global mean normalization (GMN) of PET data reveals disease-based differences from healthy individuals as fractional changes across regions relative to a global mean. To assess the impact of GMN applied to metabolic data, we compared CMRglc with and without GMN in healthy awake volunteers with eyes closed (i.e., control) against specific physiological/clinical states, including healthy/awake with eyes open, healthy/awake but congenitally blind, healthy/sedated with anesthetics, and patients with disorders of consciousness. Without GMN, global CMRglc alterations compared to control were detected in all conditions except in congenitally blind where regional CMRglc variations were detected in the visual cortex. However, GMN introduced regional and bidirectional CMRglc changes at smaller fractions of the quantitative delocalized changes. While global information was lost with GMN, the quantitative approach (i.e., a validated method for quantitative baseline m...
Source: Neural Plasticity - Category: Neurology Authors: Tags: Neural Plast Source Type: research