Myelin, myelination, and corresponding magnetic resonance imaging changes.

Accurate diagnosis of white matter diseases requires a thorough understanding of white matter maturation. These maturational changes are complex and require knowledge of the histologic background and time course of development. This article reviews the in vivo magnetic resonance (MR) appearance of myelination with emphasis on the appearance of different regions of the brain using various pulse sequences at different developmental time points. The appearance of white matter, using the MR pulse sequences that have been shown to be most useful during the stages of myelination, is also discussed.