RT Journal Article SR Electronic T1 Myelination in Children with Partial Deletions of Chromosome 18q JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology SP 447 OP 454 VO 26 IS 3 A1 Jack L. Lancaster A1 Jannine D. Cody A1 Trevor Andrews A1 L. Jean Hardies A1 Daniel E. Hale A1 Peter T. Fox YR 2005 UL http://www.ajnr.org/content/26/3/447.abstract AB BACKGROUND AND PURPOSE: We compared myelin levels in white matter (WM) in typically developing children with those of children with partial deletions of chromosome 18q (18q−).METHODS: Conventional spin-echo MR imaging at 1.9T was used to acquire T1-, T2-, and proton density-weighted images of the brain. From these images, a three-pool model was used to estimate the fraction of water in myelin, myelinated axon, and mixed water compartments (or pools) in six WM regions. A model curve was fit to the pool fractions to model the trend of myelin development by age in each region. Water-pool fractions in children with 18q− aged 5 months to 13 years were compared with those of age-matched, typically developing children.RESULTS: In children with 18q−, the model predicted later onset of myelination (P < .02), lower myelination rates (P < .001), and smaller equilibrium myelin pool fractions (P < .001). Significant differences were seen between the two groups for all three water pool fractions (P < .001). The mixed pool fraction was larger in children with 18q−. Although the myelin pool fraction was significantly smaller, the myelinated axon pool fraction was only slightly smaller, leading to a significantly smaller estimate of myelin per myelinated axon in children with 18q− (P < .001).CONCLUSION: Myelination modeling in 18q− children indicated delayed onset, a lower rate of myelination, and equilibrium myelin levels less than 50% those of age-matched, typically developing children.