Quantifying development: Investigating highly myelinated voxels in preadolescent corpus callosum

Multi-echo T2 relaxation decay data was acquired for 5 preadolescent males (age range 9–12 years). A signal to noise filter appropriate for multi-exponential T2 analysis was then applied to remove voxels which did not accurately fit the modelled curve. The remaining voxels were designated “highly myelinated” if their myelin water fraction (MWF) was greater than a critical value. We investigated a range of signal to noise filter cut-off values and highly myelinated critical values and demonstrated a significant correlation (r = 0.990, p < 0.001) between verbal intelligence quotient scores on the Wechsler Intelligence Scale for Children — Revised and myelination of the corpus callosum in children. This relationship is supported by a growing number of studies showing a correlation between white matter development and cognitive ability.