Quantitative magnetic resonance characterization of mesial temporal sclerosis in childhood

Objective: To investigate whether quantitative MR techniques can be used to distinguish between mesial temporal sclerosis in patients with a history o f prolonged febrile convulsion and in patients without such a history. Meth ods: Quantitative hippocampal T2 relaxometry, hippocampal volumetry, and si ngle voxel H-1-MRS data were acquired from 16 children who subsequently und erwent temporal lobe resections for intractable temporal lobe epilepsy and histologically were shown to have sclerosis of the horn of Ammon. Eight chi ldren had a history of prolonged febrile convulsion in early childhood and eight children had other or no associations. Results: Patients with a histo ry of prolonged febrile convulsion had smaller hippocampi (p = 0.02) and pr olonged T2 relaxation time (p = 0.03) ipsilateral to the seizure focus when compared with patients without such a history. There was also more slide-t o-side asymmetry of T2 relaxation time (p = 0.004) and hippocampal volume ( p = 0.02) in the patients with a history of prolonged febrile convulsion th an in those with other or no associations. No differences between the group s were identified using H-1-MRS. Conclusions: These data support the view t hat there are at least two types of mesial temporal sclerosis. There may be several pathogenetic pathways from initial insult to later mesial temporal sclerosis, and these pathways are, at least in part, dependent on the init ial insult.