Brain Advance Access originally published online on July 28, 2009
Brain 2009 132(10):2785-2797; doi:10.1093/brain/awp187
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Frequency, prognosis and surgical treatment of structural abnormalities seen with magnetic resonance imaging in childhood epilepsy
1 Department of Biology, Northern Illinois University, DeKalb, IL 60115, USA 2 Department of Neurosurgery, The Mental Retardation Research Center and the Brain Research Institute, University of California, Los Angeles, CA, USA 3 David Geffen School of Medicine, University of California, Los Angeles, CA, USA 4 Department of Radiology, Yale School of Medicine, New Haven, CT, USA 5 Department of Neurology, Connecticut Children's Medical Center, Hartford, CT, USA 6 Department of Neurology, Yale School of Medicine, New Haven, CT, USA 7 Department of Pediatrics, Yale School of Medicine, New Haven, CT, USA
Corresponding Author: Anne T. Berg, PhD, Department of Biology, Northern Illinois University, DeKalb, IL 60115, USA E-mail: atberg{at}niu.edu
The epidemiology of lesions identified by magnetic resonance imaging (MRI), along with the use of pre-surgical evaluations and surgery in childhood-onset epilepsy patients has not previously been described. In a prospectively identified community-based cohort of children enrolled from 1993 to 1997, we examined (i) the frequency of lesions identified by MRI; (ii) clinical factors associated with ‘positive’ MRI scans; and (iii) the utilization of comprehensive epilepsy evaluations and neurosurgery. Of the original cohort of 613 children, 518 (85%) had usable MRI scans. Eighty-two (16%) had MRI abnormalities potentially relevant to epilepsy (‘positive’ scans). Idiopathic epilepsy syndromes were identified in 162 (31%) of whom 3% had positive scans. The remainder had non-idiopathic epilepsy syndromes of which 22% had positive MRI findings. Multiple logistic regression analysis identified non-idiopathic epilepsy and abnormal motor-sensory (neurological) examinations as predictors of a positive MRI scan. Of the non-idiopathic patients with normal neurological exams and who were not pharmacoresistant, 10% had positive MRI scans, including four patients with gliomas. Evaluations at comprehensive epilepsy centres occurred in 54 pharmacoresistant cases. To date 5% of the imaged cohort or 8% of non-idiopathic epilepsy patients have undergone surgical procedures (including vagal nerve stimulator implantation) to treat their epilepsy (n = 22) or for tumours (n = 6) without being drug resistant. Applying our findings to the general population of children in the USA, we estimate that there will be 127/1 000 000 new cases per year of pharmacoresistant epilepsy, and 52/1 000 000 childhood-onset epilepsy patients undergoing epilepsy evaluations. In addition, approximately 27/1 000 000 will have an epilepsy-related surgical procedure. These findings support recommendations for the use of MRI in evaluating newly diagnosed paediatric epilepsy patients, especially with non-idiopathic syndromes, and provide estimates on the utilization of comprehensive evaluations and surgery.
Key Words: epidemiology; mesial temporal sclerosis; cortical malformation; epilepsy surgery; pharmacoresistance
Abbreviations: HA, hippocampal atrophy; ILAE, International League Against Epilepsy; MCD, malformations of cortical development; MTS, mesial temporal sclerosis; TLE, temporal lobe epilepsy; VNS, Vagal nerve stimulators
Received February 7, 2009. Revised May 28, 2009. Accepted June 10, 2009.