Abstracts

Rationale: Cryptogenic West syndrome (C-WS) has normal development before the onset, and no structural abnormalities are observed on conventional MRI. However, seizure and developmental outcome is very diverse. Diffusion tensor imaging (DTI) is an MRI technique that can provide information about white matter fiber orientation and integrity. We prospectively performed DTI to assess white matter abnormalities in patients with C-WS. The results were compared with EEG abnormalities and seizure outcome. Methods: We studied 14 consecutive patients with C-WS. DTI was acquired using 3T MRI (3.0T Trio, Siemens) at 12 months of age, and fractional anisotropy (FA) images were constructed. FA images in patients were compared with those of 12 controls. 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. Individual FA data were then projected onto the skeleton, and then correction for multiple comparisons was performed. Regions with significant differences were identified with threshold: p<0.05. Then we calculated the value of FA, and axial, radial, and mean diffusivity in the skeleton with significant difference on TBSS. We compared the each parameter between patients with and without EEG abnormalities at 12 months of age. Results: The patients showed significantly decreased FA in corpus callosum, deep white matters, and fronto-temporal white matters. Radial diffusivity was increased in the skeleton with significant difference. Seven patients showed EEG abnormalities at 12 months, and 5 of them had relapse of seizures. Patients with EEG abnormalities had lower FA and higher radial diffusion than those of patients with normal EEG at 12 months. Conclusions: Decreased FA and increased radial diffusion were observed in C-WS, especially with EEG abnormalities and seizures after initial treatments. Increased radial diffusion may reflect delayed myelination or white matter damage by epileptic activities. Persistent EEG abnormalities and seizures may affect white matter maturation in C-WS.