T2 RELAXATION-TIME AS A MARKER OF BRAIN MYELINATION - EXPERIMENTAL MRSTUDY IN 2 NEONATAL ANIMAL-MODELS

The progress of myelination in the brain was evaluated by visualizatio n of grey/white matter differentiation on magnetic resonance (MR) imag es and quantitative analysis of MR data. In vivo quantitative MR imagi ng was used to monitor the T2 transverse relaxation time changes assoc iated with cerebral development and myelination. The progress of myeli nation was evaluated using two neonatal animal models, the monkey and the dog, known to mature at very different rates. Three beagles were s tudied from birth to 4 months of age and nine baboons from 1 to 30 mon ths of age. The T2 values in the frontal, parietal and occipital white matter were calculated and the changes in these values with age were followed. Brain maturation in both species was found to correspond to decreasing T2 values in both grey and white matter. This decrease was observed both in the dog brain and, despite slower maturation, in the baboon brain, and appeared to fit with the myelination process in thes e models. Exploiting the physicochemical parameters of water in tissue s via T2 determination is a convenient and reliable strategy for the d ocumentation of brain development in both experimental approaches and clinical situations. (C) 1997 Elsevier Science B.V.