Proton magnetic resonance relaxation times T1 and T2 related to postmortem interval. An investigation on porcine brain tissue.

In order to establish the validity of in vitro determination of the proton magnetic resonance (MR) relaxation times T1 and T2 in brain tissue at increasing time delay after death or operative excision, 81 brain tissue samples from 23 pigs were analyzed repeatedly. These samples, representing cortex, caudate nucleus and white matter, were studied microscopically after MR measurements. The T1 values exhibited no time dependence and the T2 values decreased slightly during the interval 2 to 90 hours after death. The samples were stored at +8 degrees C between the measurements. These results indicate that reliable in vitro measurements can be obtained in autopsy or surgical brain tissue specimens within 90 hours after death or excision, if handled properly.