Prospects for imaging-related biomarkers of human epileptogenesis: a critical review

Abstract

To facilitate the study of epileptogenesis in humans, noninvasive biomarkers of epileptogenesis are required. No validated biomarker is currently available, but brain imaging techniques provide many attractive candidates. In this article we examine the imaging features of temporal lobe epilepsy, focusing on those that may precede the onset of epilepsy and correlate with epileptogenesis. Hippocampal volumetry and T(2) relaxometry are proposed as candidate biomarkers of epileptogenesis in temporal lobe epilepsy following febrile status epilepticus. Preliminary data suggest that these have promise, and the ongoing Consequences of Prolonged Febrile Seizures in Childhood (FEBSTAT) study will provide more conclusive evidence as to their validity. At this time there are no other clear candidates for imaging-related biomarkers of epileptogenesis in human studies.

Figure 1. Hippocampal atrophy following febrile status epilepticus

Coronal T₂-weighted magnetic resonance images obtained (A) 2 days and (B) 9 months after febrile status epilepticus in a 2-year-old girl. Initial imaging demonstrates asymmetric enlargement of the right hippocampus with abnormal T₂-weighted signal intensity (A). On delayed imaging, the right hippocampus, which continues to demonstrate abnormal T₂-weighted signal intensity, has decreased in size and is asymmetrically small (B). This patient subsequently developed temporal lobe epilepsy. Adapted with permission from [35].