Accuracy of MR imaging and CT in evaluation of seizure disorders

Three hundred sixty-eight patients with seizure disorder were studied with computed tomography (CT) and magnetic resonance (MR) imaging. CT showed a primary brain tumor in 36 patients (aged 21 - 78 years), infarctions in 42 (24 - 78 years), metastases to the brain in 42 (38 - 78 years), arteriovenous malformations and aneurysms in six (15 - 42 years), old scars from infarctions and/or trauma in ten (38 - 71 years), and acute small posttraumatic hematoma in two (10 and 19 years). Findings were negative in the remaining 230 cases. MR studies showed all of the above lesions and also demonstrated brain tumors in six cases, hamartoma in two (5 and 11 years), temporal lobe sclerosis in three (9 - 15 years) occult vascular malformation in three (21 - 28 years), and vanishing temporal lobe lesions in two (six and 18 years), out of the 230 cases with negative CT scans. Thus, the CT scans were positive in 138 cases and negative in 230, missing 18 cases with lesions detected only by MR imaging. In two cases, lesions detected with MR imaging did not appear on follow-up MR studies (6 - 8 weeks) and were assumed to be postseizure changes. Lesions shown on MR studies obtained shortly after seizure should therefore be followed up before surgical intervention is considered, as some of these may not appear on follow-up MR studies