Magnetic resonance studies in human brain oedema following administration of hyperosmotic agents. Special references to relaxation times and proton MRS.

Changes of proton relaxation times (T1 and T2) and proton Magnetic Resonance Spectroscopy (MRS) were studied in patients with brain oedema following administration of hyperosmotic agents. Relaxation times of oedema tended to decrease following infusion of hyperosmotic agents. In most patients examined, changes of relaxation times tended to achieve their lowest value at 30-60 minutes after infusion. However, the changes of relaxation times were not uniform. In some patients, relaxation times continued to decrease for more than 2 hours, while in other patients relaxation times which had earlier decreased subsequently had increased at 2 hours. The peak of water components, obtained by SIDAC (Spectroscopic Imaging by Dephasing Amplitude Changing) method was observed to change as did relaxation times. Changes of relaxation times and the peak of water components, obtained by SIDAC (Spectroscopic Imaging by Dephasing Amplitude Changing) method was observed to change as did relaxation times. Changes of relaxation times and the peak of water component may vary depending upon factors including the kinds of lesions causing oedema, phase of oedema (acute or chronic), etc. Proton relaxation times and the peak of water component obtained by proton MRS were useful in evaluating the changes of oedematous area.