Abstracts

West syndrome is an age-dependent epileptic encephalopathy with multiple etiology and with diverse psychomotor outcome. In spite of aggressive studies by many investigators, its pathophysiology still remains to be unknown. Although it is classified as a generalized epileptic syndrome because of the generalized EEG abnormalities, some authors have suggested the presence of focal cortical lesion, resection of which terminates spasms, and the participation of subcortical structures evolving spasms. We tried to evaluate objective ictal blood flow change with subtraction ictal SPECT which was made by subtracting interictal images from ictal ones., We tried subtraction ictal SPECT on 11 patients ,including 8 symptomatic cases, with West syndrome. Just after spasms are observed to repeat over 2 times, we have injected tracer, 99mTc-ethyl cysteinate dimmer (ECD). In case 11, we could also get [ldquo]pre-ictal image[rdquo], where spasms appeared soon after the tracer injection for interictal image. This was compared to the ictal images., Two cases, including case 11, showed focal ictal hyperperfusion corresponding to the areas of heterotopia on MRI and/or focal epileptic discharges detected by EEG. Other 10 cases had non-specific diffuse increase of cerebral blood flow probably due to secondary propagation of epileptic discharges. The ictal hyperperfusion of subcortical structures including basal ganglia/thalamus and brain stem was observed in 5 and 4 cases, respectively. Two cases with focal cortical hyperperfusion are also accompanied by the hyperperfusion of the subcortical areas., This study for the first time revealed the ictal activation of subcortical structures by using subtraction ictal SPECT. The results support the hypothesis in which genesis of spasm is related to subcortical structures. Two cases with hyperperfuison of both focal cortical and subcortical areas are suggestive that focal cortical epileptic activities trigger generation of spasms via subcortical systems., (Supported by Research Grant (16A-3) for Nervous and Mental Disorders from the Ministry of Health, Labour and Welfare, Japan.)