MRI signs of hippocampal sclerosis seen in healthy volunteers

Abstract

Mesial temporal lobe epilepsy (MTLE) is the most frequent partial epilepsy among adults and is highly associated with hippocampal sclerosis (HS).1 Other temporal and extratemporal regions are known to be affected in patients with MTLE, mainly those with anatomic and functional connections to the hippocampus.2,3 MRI signs of HS, both hippocampal atrophy and hyperintense T2-weighted or fluid-attenuated inversion recovery (FLAIR) signal, may be found in patients with MTLE with good seizure control with antiepileptic drug (AED) treatment.4 By contrast, there are some patients with refractory MTLE and clearly localized EEG abnormalities in whom MRI is normal and HS is diagnosed on postoperative histopathology.2 This seemingly paradoxical relationship between the presence and intensity of MRI signs of HS and the presence and frequency of seizures is not yet fully understood. It is intuitive to assume that MTLE, HS, and response to AED therapy depend on a complex mix of multifactorial underlying conditions. Understanding these biologic factors is crucial for better care of individuals with MTLE. It is equally important to know whether some of …