Abstracts

Rationale: RATIONALE: Focal cortical dysplasia (FCD) is the most common cause of intractable focal epilepsy in children. Surgical resection is an important treatment option, but this requires radiological delineation of the lesion such that complete resection can be achieved. However, despite advanced multimodal neuroimaging, the radiological localization of FCD remains challenging. Methods: METHODS: We retrospectively reviewed preoperative brain MRI, interictal PET, ictal & interictal SPECT, and FCD type (ILAE classification) of 34 children who were operated on for FCD at the Children's Hospital Colorado between 2009 and 2013, and correlated these factors with Engel Classification outcome. Results: RESULTS: The mean age at presentation was 3.7 years, while the mean age at surgery was 9.6 years, and the male-to-female ratio was 21:13. Only four (11.8%) patients had FCD localized to the mesial temporal lobe, while the other 30 (88.2%) were extra-temporal. Brain MRI, PET, and SPECT detected an abnormality in 21 (61.8%), 30 (88.2%), and 27 (79.4%), respectively. The final surgical procedure performed was lobectomy/lesionectomy in 19 (55.9%) cases, functional hemispherectomy in 13 (38.2%) cases, and a limited frontal disconnection in one (2.9%) case. Pathological analysis revealed 18 (52.9%), 8 (23.5%), and 8 (23.5%) children with FCD types 1, 2, and 3, respectively. With a mean follow-up of 38.1 months, Engel class 1 was achieved in 70.6% of children, while class 2, 3, and 4 was achieved in 8.8%, 11.8%, and 8.8%, respectively. Using multinomial regression analysis, we found that neither FCD type, nor results from MRI, PET, or SPECT alone predict outcome following epilepsy. Even when PET and SPECT both revealed abnormalities for given patients, this did not correlate with improved outcomes. Finally, neither FCD type, nor MRI findings, correlated with the ability of PET and SPECT to detect signal abnormalities. Conclusions: CONCLUSIONS: Positive results of MRI, PET, SPECT and FCD type do not predict seizure outcome following epilepsy surgery for children with focal cortical dysplasia. However, the weakness of this study is its small sample size and retrospective design.