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Author Spotlight: Advancing Pediatric Epilepsy Surgery in Children Through Novel Biomarkers and Enhanced Localization
Published on: September 20, 2024
Limited utility of structural MRI to identify the epileptogenic zone in young children with tuberous sclerosis
Maaike Nijman1, Edward Yang2, Camilo Jaimes2
1Localization Laboratory, Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Insights
Identifying the epileptogenic zone in young children with tuberous sclerosis complex (TSC) is crucial for epilepsy surgery success. Structural MRI alone has limited utility, but combining it with electroencephalography (EEG) improves identification of the seizure-causing tuber.
Area of Science:
- Pediatric Neurology
- Neuroimaging
- Epileptology
Background:
- Tuberous sclerosis complex (TSC) is a genetic disorder associated with epilepsy.
- Accurate identification of the epileptogenic zone (EZ) is critical for successful epilepsy surgery in children with TSC.
- Current methods for identifying the EZ using structural MRI in young children with TSC have limitations.
Purpose of the Study:
- To evaluate the utility of structural magnetic resonance imaging (MRI) features in identifying the epileptogenic zone (EZ) in young children with TSC.
- To determine if combining MRI with electroencephalography (EEG) data improves EZ identification.
- To assess the characteristics of tubers and focal cortical dysplasia (FCD) features predictive of the EZ.
Main Methods:
- Retrospective review of preoperative MRI scans from 26 children with TSC who underwent epilepsy surgery before age 3.
- Two neuroradiologists assessed candidate lesions for tuber and FCD features, blinded to surgical outcomes.
- Lesions were selected based on structural MRI and re-evaluated after unblinding to EEG seizure onset data.
Main Results:
- Neither tuber characteristics nor FCD features were distinctive for the EZ in seizure-free children.
- Structural MRI alone identified the EZ in 31% of cases; this increased to 48% with the addition of EEG data.
- Interrater agreement for lesion features was moderate to fair, highlighting variability in interpretation.
Conclusions:
- Structural MRI features have limited utility for identifying the epileptogenic tuber in young children with TSC.
- Combining structural MRI with EEG data significantly improves the identification of the EZ.
- Further research may refine imaging biomarkers for improved surgical planning in pediatric TSC.
Background And Purpose:
The success of epilepsy surgery in children with tuberous sclerosis complex (TSC) hinges on identification of the epileptogenic zone (EZ). We studied structural MRI markers of epileptogenic lesions in young children with TSC.
Methods:
We included 26 children with TSC who underwent epilepsy surgery before the age of 3 years at five sites, with 12 months or more follow-up. Two neuroradiologists, blinded to surgical outcome data, reviewed 10 candidate lesions on preoperative MRI for characteristics of the tuber (large affected area, calcification, cyst-like properties) and of focal cortical dysplasia (FCD) features (cortical malformation, gray-white matter junction blurring, transmantle sign). They selected lesions suspect for the EZ based on structural MRI, and reselected after unblinding to seizure onset location on electroencephalography (EEG).
Results:
None of the tuber characteristics and FCD features were distinctive for the EZ, indicated by resected lesions in seizure-free children. With structural MRI alone, the EZ was identified out of 10 lesions in 31%, and with addition of EEG data, this increased to 48%. However, rates of identification of resected lesions in non-seizure-free children were similar. Across 251 lesions, interrater agreement was moderate for large size (κ = .60), and fair (κ = .24) for all other features.
Conclusions:
In young children with TSC, the utility of structural MRI features is limited in the identification of the epileptogenic tuber, but improves when combined with EEG data.
