Proton relaxation time of immature brain. I. Measurement of proton relaxation time (T1 and T2) in immature rat brain by 1H-NMR spectroscopy.

It is generally accepted that the water content in the brain tissue of immature animals is so great as to be responsible for the prolongation of proton relaxation time, namely, the spin-lattice relaxation time (T1) and the spin-spin relaxation time (T2). In assessing edema in the immature rat brain with the passage of time, we measured the water content, T1, and T2, and then compared these parameters with those in rats aged 5 weeks. Traumatic cerebral edema was experimentally produced in immature rats aged 7 days (group A) and mature rats aged 5 weeks (group B). In group A, the water content of the gray matter and the white matter increased significantly on the 1st day after the development of experimental brain edema, continued at a high level in white matter, but normalized in gray matter on the 7th day. On the other hand, for group B, the water content of gray and white matter also increased significantly 1 day after the production of the brain edema, but was reduced to within the normal range on the 7th day for both regions.