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

Purpose: To establish age limits For the assessment of normal myelination of 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, Hayakawa et al. 1990, Hittmair et at. 1994, Martin et al. 1988/1990/1991. Nakagawa et al. 1998, Staudt et al. 1993/1994, Stricker et al. 1990). Results: Despite technical and methodological differences, these studies principally 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 cerebellar peduncles, thalamus, posterior limb of internal capsule, optic radiation, corona radiata. Thereafter, the myelin-typical signal in the different regions of the brain should be present at the following ages (M = months): anterior limb of internal capsule (2 M: T(1)w; 7 M: T(2)w), splenium of corpus 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 myelin 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 more reliable assessment of myelination than the time-tables from a single study.