[The MR evaluation of normal children and disorders of neuronal migration and myelination]

We often experience the case that is difficult to differentiate normal from abnormal myelinating process by CT scan, because the diagnosis of myelinating maturation of the infant during developmental process is confusing. We can understand maturation of myelination adding to the advancement of diagnostic resolution by MR imager. So we obtain more informations about the abnormality of myelination and development of the brain by MR imaging than CT scan. This study demonstrates the ability of MR imaging to show progression of myelination in 10 infants and children. We also reveals the patients with disorders of neuronal migration or myelination during developing process. MR scanning could be obtained by sedation using such as triclofos or chloral hydrate for infant and younger children. It was necessary to use diazepam or pentazocine intravenously for elder children with mental retardation or restlessness. MR scans were performed with Siemens MAGNETOM 1.5 Tesla. T 1-weighted spin echo image (TR 600/TE 15) and T 2-weighted image (TR 3000/TE 90) were obtained for all cases. The ten normal infants and children (7 boys, 3 girls) were aged from 1 month to 4 years. Maturation of white matter generally proceeded from posterior limb of internal capsule to middle cerebellar peduncle, cerebellar white matter, corpus callosum, anterior limb of internal capsule, occipital white matter, centrum semiovale, finally frontal white matter. Myelination was matured during the first two years by T 2-weighted images. Changes caused by brain myelination were seen earlier on T 1-weighted images (7 months after birth) than on T 2-weighted images (one year and 9 months after birth).(ABSTRACT TRUNCATED AT 250 WORDS)