Normal myelination of the child brain on MRI - A Meta-analysis

Purpose: To establish age limits For the assessment of normal myelination o f the brain on T-1-weighted (T(1)w) and T-2-weighted (T(2)w) images. Method : Comparison of previous publications (Barkovich et al. 1988, Grodd 1993, H ayakawa et al. 1990, Hittmair et at. 1994, Martin et al. 1988/1990/1991. Na kagawa et al. 1998, Staudt et al. 1993/1994, Stricker et al. 1990). Results : Despite technical and methodological differences, these studies principal ly agreed on the timing of myelination for most regions of the brain. Thus, a common timetable could be established: At 1 month, myelin is visible on both T(1)w and T(2)w in the medulla oblongata, tegmentum pontis, cerebellar peduncles and vermis, quadrigeminal plate, decussation of superior cerebel lar peduncles, thalamus, posterior limb of internal capsule, optic radiatio n, corona radiata. Thereafter, the myelin-typical signal in the different r egions of the brain should be present at the following ages (M = months): a nterior limb of internal capsule (2 M: T(1)w; 7 M: T(2)w), splenium of corp us callosum (4 M: T(1)w; 6 M: T(2)w), genu of corpus callosum (6 M: T(1)w; 8 M: T(2)w), centrum semiovale (2 M: T(1)w; 7 M: T(2)w). Branching of myeli n into the gyri of the telencephalon (= arborization) appears at the latest at: occipital robe (5 M: T(1)w; 12 M: T(2)w) and frontal lobe (7 M: T(1)w; 14 M: T(2)w). Conclusion: These extracted age limits can be used for a mor e reliable assessment of myelination than the time-tables from a single stu dy.