Abstract
BACKGROUND AND PURPOSE: Patients with MR imaging-negative epilepsy could have subtle FCD. Our aim was to determine if structural changes could be identified by using DTI in children with intractable epilepsy, from MR imaging-visible FCD and MR imaging-negative localization-related epilepsy, that were concordant with the epileptogenic zone as defined by using the MEG dipole cluster.
MATERIALS AND METHODS: Eight children with MR imaging-visible FCD and 16 with MR imaging- negative epilepsy underwent DTI and MEG. Twenty-six age-matched healthy children underwent DTI. Analysis was performed on controls across individual patients. Agreement between the location of DTI abnormalities and FCD and MEG dipole clusters was assessed.
RESULTS: In patients with MR imaging-visible FCD, abnormal FA, MD, λ1, λ2, and λ3 were lobar concordant with the MEG dipole cluster in 4/8 (50.0%), 5/8 (62.5%), 3/8 (37.5%), 6/8 (75.0%), and 5/8 (62.5%), respectively. In patients with MR imaging-visible FCD, abnormal FA, MD, λ1, λ2, and λ3 overlapped the x-, y-, and z-axes of the MEG dipole cluster in 1/8 (12.5%), 4/8 (50%), 4/8 (50%), 6/8 (75%), and 4/8 (50%), respectively, and with FCD in 1/8 (12.5%), 3/8 (37.5%), 0/8 (0%), 3/8 (37.5%), and 1/8 (12.5%), respectively. In patients with MR imaging-negative epilepsy, abnormal FA, MD, λ1, λ2, and λ3 were lobar-concordant with the MEG dipole cluster in 11/16 (68.8%), 11/16 (68.8%), 8/16 (50.0%), 10/16 (62.5%), and 10/16 (62.5%), respectively, and overlapped the x-, y-, and z-axes of the MEG dipole cluster in 9/16 (56.3%), 10/16 (62.5%), 8/16 (50%), 8/16 (50%), and 8/16 (50%), respectively. There was no significant difference between abnormal DTI lobar concordance with the MEG dipole cluster in patients with MR imaging-visible FCD and MR imaging-negative epilepsy.
CONCLUSIONS: White matter changes can be detected with DTI in children with MR imaging-visible FCD and MR imaging-negative epilepsy, which were concordant with the epileptogenic zone in more than half of the patients.
Footnotes
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- EEG
- electroencephalography
- FA
- fractional anisotropy
- FCD
- focal cortical dysplasia
- FLE
- frontal lobe epilepsy
- FMRIB
- Functional MR Imaging of the Brain Library
- λ1, λ2, and λ3
- eigenvalues
- MD
- mean diffusivity
- MEG
- magnetoencephalography
- MNI
- Montreal Neurological Institute
- SPM
- statistical parametric mapping
- TBSS
- tract-based spatial statistics
- TLE
- temporal lobe epilepsy
- VBM
- voxel-based morphometry
- © 2011 American Society of Neuroradiology