Changes within the "normal" cerebral white matter of multiple sclerosis patients during acute attacks and during high-dose cortisone therapy assessed by means of quantitative MRI.

Changes in the apparently unaffected cerebral white matter of multiple sclerosis (MS) patients were studied during acute attacks as well as during high-dose prednisolone therapy. Serial MR scans of patients with a clinically definite diagnosis were performed on four defined occasions: before an episode, within three days after its onset, after 10 days of therapy as well as four weeks later. Thirteen patients agreed to cooperate in forming a MRI data base and to be rescanned immediately after the onset of an acute relapse. Within one year, six patients had such episodes, one of them had a second bout. Both T1 and T2 relaxation times within the apparently normal white matter were significantly prolonged in all cerebral lobes compared to a control group of healthy volunteers. During the acute attacks as well as during therapy the T1 values remained as before. The T2 values were elevated only in two out of six cases during the episode. After therapy a considerable clinical improvement was seen in all cases, but a significant T2 decrease as a possible effect of cortisone was noted in only one case. We conclude that the prolonged relaxation times T1 and T2 within the apparently normal cerebral white matter of MS patients are the result of a number of molecular events differing considerably among individual patients and that serial measurements of these relaxation times do not consistently change during an acute relapse and do not reflect clinical improvement after high dose prednisolone therapy.