Ictal SPECT in children with partial epilepsy due to focal cortical dysplasia

We studied the usefulness of ictal single-photon emission computed tomography in the presurgical evaluation of children with partial epilepsy resulting from focal cortical dysplasia. Fifteen children, age 1-18 years, were identified with partial epilepsy caused by focal cortical dysplasia (confirmed by histology) who underwent subtraction ictal single-photon emission computed tomography during presurgical evaluation. All children later underwent surgery at the Cleveland Clinic Epilepsy Center between 1996 and 2000. The findings of ictal single-photon emission computed tomography and brain positron emission tomography were classified as localized when "localizing and concordant" with the surgical resection site, nonconcordant when "localizing but not concordant" with the surgical resection, or nonlocalized when "no well-localized region of ictal hyperperfusion was observed on the difference image". In 15 patients, age 1.5-18 years (median age 8 years), epilepsy was classified as frontal in 7, posterior temporal/occipital in 3, temporal in 2, multilobar in 2, and parietal in 1. Of 15 patients, preoperative magnetic resonance imaging revealed focal cortical dysplasia in 11, positron emission tomography was localized in 9, and ictal single-photon emission computed tomography was localized in 8 patients. In 4 patients with normal magnetic resonance imaging but scalp electroencephalographic findings of partial epilepsy, ictal single-photon emission computed tomography and positron emission tomography were localized in 3 each. Fourteen patients were monitored for 6-39 months (mean 20 months). Six of 7 patients (85%) with localized ictal single-photon emission computed tomography compared with 4 of 7 (57%) with nonconcordant/nonlocalized ictal single-photon emission computed tomography had no seizures at follow-up. In 4 patients with normal magnetic resonance imaging, 3 patients with localized ictal single-photon emission computed tomography were free of seizures compared with 1 with nonconcordant ictal single-photon emission computed tomography who continued to have seizures. Ictal single-photon emission computed tomography is a useful adjunctive test in presurgical evaluation of children with refractory partial epilepsy due to focal cortical dysplasia, especially when brain magnetic resonance imaging is normal.