Diffusion anisotropy in adult and neonatal human brain

Diffusion anisotropy in adult and neonatal brain white matter was evaluated with diffusion weighted MR imaging. Six healthy adults and 8 premature-born neonates were studied using GE 1.5T SIGNA equipped with self shielded gradient coil. Cardiac gated diffusion weighted images were obtained with TR of 2 cardiac cycles in adults, 3 or 4 cardiac cycles in neonates, TE of 120 ms, and gradient factor of 450s/mm2. The direction of motion probing gradient was changed among the readout, phase encoding, or slice selection axes. Diffusion anisotropy was clearly demonstrated in all adults. Large signal attenuation was observed, when the motion probing gradient was applied in paralleled orientation to white matter fibers. In all neonates, diffusion anisotropy was nuclear in cortical and deep white matter where no myelination was demonstrated on T1 and T2 weighted images. Detection of diffusion anisotropy using diffusion weighted MR imaging was thought to be useful for the evaluation of neonatal white matter development. (author)