Abstracts

Rationale: Cryptogenic West syndrome (C-WS) has normal development before onset, and no structural abnormalities are observed on conventional MRI. However, seizure and psychomotor 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 one and two years of age. At one year of age, Tract-based spatial statistics (TBSS) analysis showed clusters of significantly decreased fractional anisotropy (FA) in widespread white matters. At two years of age, decreased FA was observed only in patients with delayed psychomotor development. To further assess white matter abnormalities at early stage of C-WS, we analyzed DTI that were obtained at the onset in patients with C-WS.Methods: We prospectively performed DTI with a 3T MRI scanner (3.0T Trio, Siemens) in 17 patients with C-WS at the onset. Mean age at the scan was 6.2 months. FA images of patients were compared with those of 12 controls with mean was 6.1 months. Statistical analysis of FA images was carried out using TBSS implemented in FSL (The Oxford FMRIB Software Library). TBSS projects all subjects' FA data onto a mean FA tract skeleton, before applying voxelwise cross-subject statistics. Regions with significant differences were identified with threshold: p<0.05.Results: TBSS analysis showed clusters of significantly increased FA in corpus callosum and deep white matters in patients. While mean FA values in the area with significant difference on TBSS positively correlated with age in controls, there is no correlation between FA values and age in patients.Conclusions: In contrast with decreased FA at one year of age, DTI at onset revealed increased FA in patients with C-WS. This finding may indicate abnormal white matter development in early infantile period of C-WS.