Normal maturation of the neonatal and infant brain: MR imaging at 1.5 T.

TLDR

The study investigated the pattern of normal white‑matter maturation using high‑field MR imaging. Eighty‑two neurologically normal infants aged 4 days to 2 years were scanned on a 1.5‑T MR unit with spin‑echo T1‑ and T2‑weighted sequences, and the images were qualitatively evaluated for white‑matter changes across 14 brain regions and correlated with age. MR images revealed an orderly maturation sequence beginning in the brain stem and progressing to the cerebellum and cerebrum, with T1‑weighted changes preceding T2‑weighted ones; T2 changes best correlated with myelination, making T1 imaging most useful in the first 6–8 months and T2 after 6 months, and the study delineated normal maturation milestones while noting that persistent long T2 areas above the ventricular trigone are normal.

Abstract

The pattern of normal white-matter maturation as demonstrated with high-field-strength magnetic resonance (MR) imaging was investigated. Eighty-two neurologically normal infants were examined with a 1.5-T unit with use of spin-echo T1-weighted and T2-weighted pulse sequences. The infants ranged in age from 4 days to 2 years. The images were assessed for qualitative changes of white matter relative to gray matter in 14 anatomic areas of the brain and correlated with the patient's age. The MR images showed that changes of brain maturation occur in an orderly manner, commencing in the brain stem and progressing to the cerebellum and the cerebrum. Changes caused by brain myelination were seen earlier on T1-weighted images than on T2-weighted images, possibly because of T1 shortening by the components of the developing myelin sheaths. The later changes on the T2-weighted images correlated best with the development of myelination as demonstrated with histochemical methods. T1-weighted images were most useful in the monitoring of normal brain development in the first 6-8 months of life; T2-weighted images were more useful after 6 months. The milestones in the MR appearance of normal maturation of the brain are presented. Persistent areas of long T2 relaxation times are seen superior and dorsal to the ventricular trigone in all infants examined and should not be mistaken for ischemic change.