Epilepsy‐predictive magnetic resonance imaging changes following experimental febrile status epilepticus: Are they translatable to the clinic?

Summary Objective A subset of children with febrile status epilepticus ( FSE ) are at risk for development of temporal lobe epilepsy later in life. We sought a noninvasive predictive marker of those at risk that can be identified soon after FSE , within a clinically realistic timeframe. Methods Longitudinal T 2 ‐weighted magnetic resonance imaging (T 2 WI MRI ) of rat pups at several time points after experimental FSE (e FSE ) was performed on a high‐field scanner followed by long‐term continuous electroencephalography. In parallel, T 2 WI MRI scans were performed on a 3.0‐T clinical scanner. Finally, chronic T 2 WI MRI signal changes were examined in rats that experienced eFSE and were imaged months later in adulthood. Results Epilepsy‐predicting T 2 changes, previously observed at 2 hours after eFSE , persisted for at least 6 hours, enabling translation to the clinic. Repeated scans, creating MRI trajectories of T 2 relaxation times following eFSE , provided improved prediction of epileptogenesis compared with a single MRI scan. Predictive signal changes centered on limbic structures, such as the basolateral and medial amygdala. T 2 WI MRI changes, originally described on high‐field scanners, can also be measured on clinical MRI scanners. Chronically elevated T 2 relaxation times in hippocampus were observed months after eFSE in rats, as noted for post‐ FSE changes in children. Significance Early T 2 WI MRI changes after eFSE provide a strong predictive measure of epileptogenesis following eFSE , on both high‐field and clinical MRI scanners. Importantly, the extension of the acute signal changes to at least 6 hours after the FSE enables its inclusion in clinical studies. Chronic elevations of T 2 relaxation times within the hippocampal formation and related structures are common to human and rodent FSE , suggesting that similar processes are involved across species.