Quantification of myelin in children using multiparametric quantitative MRI: a pilot study.

PURPOSE: The purpose of this study was to evaluate the usefulness of multiparametric quantitative MRI for myelination quantification in children.

METHODS: We examined 22 children (age 0-14 years) with multiparametric quantitative MRI. The total volume of myelin partial volume (Msum), the percentage of Msum within the whole brain parenchyma (Mbpv), and the percentage of Msum within the intracranial volume (Micv) were obtained. Four developmental models of myelin maturation (the logarithmic, logistic, Gompertz, and modified Gompertz models) were examined to find the most representative model of the three parameters. We acquired myelin partial volume values in different brain regions and assessed the goodness of fit for the models.

RESULTS: The ranges of Msum, Mbpv, and Micv were 0.8-160.9 ml, 0.2-13%, and 0.0-11.6%, respectively. The Gompertz model was the best fit for the three parameters. For developmental model analysis of myelin partial volume in each brain region, the Gompertz model was the best-fit model for pons (R 2  = 74.6%), middle cerebeller peduncle (R 2  = 76.4%), putamen (R2  = 95.8%), and centrum semiovale (R 2  = 77.7%). The logistic model was the best-fit model for the genu and splenium of the corpus callosum (R 2  = 79.7-93.6%), thalamus (R 2  = 81.7%), and frontal, parietal, temporal, and occipital white matter (R 2  = 92.5-96.5%).

CONCLUSIONS: Multiparametric quantitative MRI depicts the normal developmental pattern of myelination in children. It is a potential tool for research studies on pediatric brain development evaluation.