Abstracts

Rationale: Cryptogenic West syndrome (C-WS) has normal development before onset, and no structural abnormalities are observed on conventional MRI. However, seizure and developmental outcome in C-WS is very diverse. Diffusion tensor imaging (DTI) can provide information about white matter fiber orientation and integrity. We have demonstrated white matter abnormalities on DTI in patients with C-WS at onset. Tract-based spatial statistics (TBSS) analysis showed clusters of significantly increased fractional anisotropy (FA) in corpus callosum and deep white matters in patients. To reveal longitudinal change of white matter microstructures in patients with C-WS, we analyzed DTI obtained at the onset, 12 months and 24 months of age in patients with C-WS. Methods: We prospectively performed DTI with 3T MRI scanner in 17 patients with C-WS at onset, 12 months and 24 months of age. Regions of interest (ROIs) were set on genu, body and splenium of corpus callosum. We measured mean FA of ROIs by using tracking softwares, dTV and VOLUME-ONE. FA values in patients were compared with those of 37 controls aged from 2 to 24 months. Results: The FAs of genu and body of corpus callosum were higher in patients at onset, especially in patients with younger age. The FA values became lower in patients at 12 months of age compared with those of controls. While FAs at onset did not correlate with developmental quotients, FAs at 12 and 24 months of age positively correlated with developmental quotients. Conclusions: Elevation of FA at onset suggests cytotoxic edema of immature white matters caused by epileptic encephalopathy. As a result, microstructural damage or delayed maturation of white matters occurs and causes delayed psychomotor development at 1 and 2 years of age.