[Proton relaxation characteristics of human and animal tissue in vitro. Changes during autolysis and fixation].

The results of measurements of proton relaxation times of various tissues from rats, pigs and humans are reported; these were obtained by a resonance spectroscope at 20 MHz and 40 degrees C. There were specific differences in both relaxation times (T1 and T2) of the liver and spleen. There was a difference of more than 150 ms in the longitudinal relaxation time between grey and white cerebral tissue. Autolytic changes show an increase in both relaxation times. Fixation produced a reduction in T1 only. The significance of these findings for NMR tomography is discussed.