Abstracts

We sought to determine the age at which mesial temporal sclerosis (MTS) can be identified using MRI in children with seizure disorders, and to assess the factors associated with MTS in children. We reviewed records in 104 children with MTS identified by MRI performed to evaluate children with a history of seizures. MRI was performed at 1.5T and included a high resolution oblique coronal Fast Spin Echo sequence perpendicular to the hippocampal formation. MRI studies were reviewed by a pediatric neuroradiologist blinded to patient identity. Studies were scored on a scale of 1-5 (1 normal, 2 probably normal, 3 equivocal, 4 probably abnormal, 5 abnormal) for both signal and atrophy. Scans with a score of 4 or 5 for both signal and volume were determined to have MTS. Patients were identified between 1993 and 2004. Records were reviewed for associated risk factors. Mean age at age at MRI study was 8.7 (SD 4.7) with a range between 0.5 and 17.5 years; Median was 8.5, and Mode was 5 and 6 years (eleven each). 35 children were found to have MTS identified by age 5 and younger. Seven children had MTS identified before two years (four during infancy). 40 children had MTS identified between 6 and 10. 12% children had bilateral MTS; 30% had a history of febrile seizures; 14% had acute illness (CNS infection, acute encephalopathy); 12% had dual pathology (perinatal stroke, dysplasia); 6% had a history of prematurity with evidence of ischemic brain injury. MTS is readily identified by high resolution MRI throughout childhood. MTS was present in one third of our patients by age 5, and may be identified during infancy. Historically MTS has been associated with risk factors that occur by age 5. Risk and causative factors may be found in nearly two thirds of children with MTS, and generally occur before age five. (Supported by NICHD 1P30HD40677)