Magnetic resonance study of brain oedema induced by cold injury--changes in relaxation times before and after the administration of glycerol.

Experiments were carried out to determine the ability of magnetic resonance systems to assess change in relaxation times following the induction of experimental brain oedema and subsequent administration of hypertonic glycerol. Nine small mongrel dogs were used for these experiments. Twenty-four hours after producing a cold lesion, magnetic resonance (MR) studies were performed and physiological data were measured. Thirty min after beginning the administration of glycerol, serum osmotic pressure was raised 88 mOsm/l. After administering glycerol a small reduction in long spin echo images was observed in the periventricular high intensity area. The T1 and T2 values appeared to be decreased from 30 min after glycerol administration. This decrease continued until the period of observation ended. Statistically significant changes in the T2 values, especially in the white matter of the opposite side, were seen. The changes in T1 were generally not statistically significant. We conclude that the changes in water content of the oedematous brain following the administration of glycerol can be detected by magnetic resonance systems, that these changes become appreciable 30 min after administration of glycerol and continue at least two more hours, and that the changes in T2 were larger than those in T1.