[Serial changes of MRI and SPECT findings in a case of adult-onset SSPE].

A 20-year-old man who had developed involuntary movement of his left hand and memorial disturbance visited our hospital in December, 1991. On admission, myoclonus, dementia and speech disturbance were recognized. He was diagnosed as subacute sclerosing panencephalitis (SSPE) based on a high titer of serum anti-measles antibody (1/256), serum anti-measles-IgG antibody (> 1/4,800) and typical EEG fiding of periodic synchronus discharge (PSD). Inosine pranobex was administrated orally (4,800mg per day). Serial cranial magnetic resonance imagings (MRI) were taken since January, 1992 to June, 1994. No abnormal finding was demonstrated until April 16, 1992 in MRI, but 123I-IMP SPECT detected decreased accumulation in parietal to occipital lobes on early image in February 5, 1992. Marked high signal area on T2 weighted image in right temporal lobe and parieto-occipital lobe were firstly demonstrated in June 22, 1992 on MRI. These high signal lesions alternated the areas and locations, but the changes were not related to his clinical symptom. These findings may suggest ischemic changes after demyelination. His symptoms have been improving gradually since June, 1994. To our knowledge, 42 cases of adult-onset SSPE were reported so far (5 were in Japan). This case is the first report in the world on adult-onset SSPE serially observed with MRI and SPECT since early stage.