Abstracts

Rationale: We examined the relation between cortical hypometabolism on FDG-PET at the onset and long-term outcome at least 10 years after onset in patients with cryptogenic West syndrome. Methods: Between 1991 and 1997, we prospectively performed serial FDG-PET studies in 20 patients with cryptogenic West syndrome. PET was performed first at the onset of epileptic spasms and second after initial treatments at 10 months of age. We performed PET scans more than one month after ACTH therapy to avoid the effect of brain shrinkage by ACTH. PET images were evaluated by visual inspection to detect cortical hypometabolism. In 2007, we evaluated psychomotor development and seizure outcome in 17 patients at 10-17 years of age; three patients were lost to follow-up. Information about the outcome was obtained from the medical records in the hospitals and by a questionnaire. Correlation between first or second PET findings and long-term outcome was evaluated. Results: At the onset, PET showed cortical hypometabolism in 11/17 patients: diffuse cortical hypometabolism in 2 and focal in the other 9. The location of the focal PET abnormality was occipito-temporal in 3 patients, temporo-parietal in 3, and fronto-temporal in 3. The second PET scans after initial treatments revealed cortical hypometabolism in 5/17 patients. The area of the hypometabolism was temporo-parietal in 2 and fronto-temporal in 3. Temporal lobe was the most frequent area where hypometabolism was present. The second PET showed normal PET findings in 6 of the 9 patients with hypometabolism at the onset. In 2 of the 6 patients with normal findings at the onset, the second PET showed focal cortical hypometabolism. At 10-17 years of age, 4/17 patients had persisted or reccurred partial seizures and 8/17 patients had mental retardation (5: moderate, 3: severe). In 12 patients with normal PET findings on the second scans, 10 were free of seizures without antiepileptic medication and 9 showed normal psychomotor development at 10-17 years of age. On the other hand, in 5 patients showing cortical hypometabolism on the second PET, 2 had persisted or recurred seizures and all 5 had mental retardation at the last follow-up period. Conclusions: The cortical hypometabolism revealed by PET is not permanent, but changes with clinical symptoms in many patients. Persistent hypometabolism after initial treatments predict poor long-term outcome in patients with West syndrome.