Myelination of the pig's brain: a correlated MRI and histological study.

Minipigs, 2, 4, 6 months old, were used to evaluate the relationship between myelination in the fiber tracts of the central nervous system (CNS) of this animal during development. Histological results showed an increased density of the myelinated fibers as well as branching of these fibers in the areas studied, including the cortical white matter, olfactory tract, the corticospinal tract, the fasciculus cuneatus and the spinal V nucleus from 2 to 6 months old. By 6 months, the pig was sexually matured. Concomitantly, there was an increase in high signal-intensity regions (sites) in the magnetic resonance T(1)-weighted images as myelination progressed. There is a good correlation between the histologically observed progress of myelination and the T(1)-weighted images in the development of the CNS of the pig. Copyright 2005 S. Karger AG, Basel.