Abstract:
From over 100 children studied with 2-deoxy-2[18F]fluoro-D-glucose
and positron emission tomography we selected 29 children (aged 5 days to
15.1 years) who had suffered transient neurological events not
significantly affecting normal neurodevelopment. These 29 children were
reasonably representative of normal children and provided an otherwise
unobtainable population in which to study developmental changes in local
cerebral metabolic rates for glucose (lCMRGlc). In infants less than 5
weeks old lCMRGlc was highest in sensorimotor cortex, thalamus,
brainstem, and cerebellar vermis. By 3 months, lCMRGlc had increased in
parietal, temporal, and occipital cortices; basal ganglia; and
cerebellar cortex. Frontal and dorsolateral occipital cortical regions
displayed a maturational rise in lCMRGlc by approximately 6 to 8 months.
Absolute values of lCMRGlc for various grey matter regions were low at
birth (13 to 25 mumol/min/100 gm), and rapidly rose to reach adult
values (19 to 33 mumol/min/100 gm) by 2 years. lCMRGlc continued to rise
until, by 3 to 4 years, it reached values of 49 to 65 mumol/min/100 gm
in most regions. These high rates were maintained until approximately 9
years, when they began to decline, and reached adult rates again by the
latter part of the second decade. The highest increases of lCMRGlc over
adult values occurred in cerebral cortical structures; lesser increases
were seen in subcortical structures and in the cerebellum. This time
course of lCMRGlc changes matches that describing the process of initial
overproduction and subsequent elimination of excessive neurons,
synapses, and dendritic spines known to occur in the developing brain.
The determination of changing metabolic patterns accompanying normal
brain development is a necessary prelude to the study of abnormal brain
development with positron emission tomography