Subacute sclerosing panencephalitis: evaluation with CT and MR.

PURPOSE To evaluate the progression of CT and MR changes of the brain in subacute sclerosing panencephalitis (SSPE) as a basis for assessing the effects of different types of therapy.

METHODS Fifty-two patients with SSPE were examined, 44 with MR imaging and 42 with CT of the brain on one or more occasions. A total of 92 MR and 67 CT studies were performed.

RESULTS Correlation between the clinical status and the MR findings in admission was poor. Of 20 patients with clinically advanced disease, only 8 had marked MR abnormalities; 6 had normal or almost normal findings on MR examinations. Two of 4 patients with clinically mild disease had advanced MR changes. The progression of the MR findings appeared to follow a constant pattern. The earliest pathologic finding was focal, high-T2-intensity white matter changes; later atrophic changes followed. The atrophy lagged behind the white matter changes and was thus mild when white matter changes were moderate or severe. In the most advanced stage, when the patient was in a neurovegetative state, an almost total loss of white matter had usually taken place. At this stage, the corpus callosum was also thin. Basal ganglia changes, usually involving the putamina, were seen in one third of patients and cortical gray matter changes were seen in one fourth of patients examined with MR imaging. In 2 of 20 patients, MR changes regressed in parallel with clinical improvement following therapy, but in 5 patients clinical improvement was accompanied by progression of MR changes.

CONCLUSION The progress of MR abnormalities seen in patients with SSPE seems to follow a constant pattern, but the severity of MR changes does not always correlate well with the clinical findings. Caution must therefore be used when evaluating the effects of therapy.