Abstracts

Rationale: Recently introduced national guidelines in the UK recommend brain magnetic resonance imaging (MRI) of all children with newly diagnosed epilepsy under the age of 2 years(1). We aimed to examine the diagnostic yield and its relationship to scan quality of such practice in a population based cohort of children with epilepsy onset in infancy. Methods: Children were enrolled as part of a population based study. All children with epilepsy onset under two years, excluding neonates, resident in 15 boroughs of North London and ascertained over a 13 months period, (N=57) were reviewed. Data on neuroimaging (organised by local physicians) of children enrolled in the ‘Epilepsy in Infancy Study’ were obtained. Neuroimages were reviewed by two experienced neuroradiologists independently, unaware of the clinical details. A structured proforma was completed requesting information on imaging sequences, planes, abnormalities seen, image-quality and indication for repeat scans. Results: Neuroimaging was performed in 55 children (96%): 54 MRI, 1 CT, 8 both. Sixty five MR images of 51 children were obtained for review. Fifty one (78.5%) MR scans had been requested to investigate epilepsy. Thirty five (55%) included T1and T2 weighted images, each in two planes, as recently recommended(2). Dedicated ‘epilepsy’ sequences such as 3-D volume T1-weighted acquisition were obtained for 19 (29%) and angulated coronal T2 weighted through long axis of hippocampi for 14 (22%) scans. Abnormalities were recognised in 37 cases (72%). Aetiologically relevant findings in 26 cases (51%) included developmental malformations (11, 21%) and acquired lesions (14, 27%). Findings thought to be incidental or aetiologically uncertain (e.g. arachnoid cysts, delayed myelination) were seen in a further 11(21%) cases. Of the 7 (11%) scans judged to be of insufficient quality 5 were repeated and 3 revealed new diagnostic information. Repeat imaging with dedicated epilepsy protocols was recommended after 23 scans (25%) if seizures persisted and focal epilepsy was suspected. Of the 14 (20%) repeat MR scans, 7 provided new information. Conclusions: MR imaging in this infant cohort revealed a high diagnostic yield. However, scan protocols have not been standardised and therefore repeat imaging was required, and provided new information, in many children. Although the recommendations of the national guidelines are supported, MR imaging protocols to investigate young children with epilepsy should be standardised in order to minimise patient risk from sedation and cost of repeating scans. (1) National Institute for Clinical Excellence. The diagnosis and management of the epilepsies in adults and children in primary and secondary care. Clinical Guideline 20. 2004. (2) Saunders DE, Thompson C, Gunny R, Jones R, Cox T, Chong WK. Magnetic resonance imaging protocols for paediatric neuroradiology. Pediatr Radiol 2007.