Epilepsy is the main complication of febrile status epilepticus (FSE) in children. The association between FSE and the development of hippocampal sclerosis (HS) and mesial temporal lobe epilepsy (MTLE) is controversial.

This study primarily aimed to evaluate the role of magnetic resonance imaging (MRI) in diffusion-weighted imaging (DWI) sequence during the acute phase of FSE in predicting long-term development of HS and epilepsy. The secondary objective was to assess the value of arterial spin labeling (ASL) perfusion MRI in the acute phase of FSE.

Patients with a first episode of FSE between 6 months and 5 years of age who underwent early MRI were retrospectively included. MRI analysis focused on the DWI signal and the presence of perfusion abnormalities on ASL imaging. We also examined the first electroencephalogram (EEG) during the acute phase. Long-term follow-up analysis assessed the occurrence of HS on MRI scans and the development of epilepsy.

A total of 15 children were included. The presence of restricted diffusion areas on MRIs performed in the acute phase after FSE was significantly associated with the later development of HS. However, the association between restricted diffusion areas on early MRIs and the development of pharmaco-resistant epilepsy on follow-up, found in 3 patients, was not statistically significant. There was a trend for an association between early ASL perfusion MRI changes and EEG findings when both examinations were performed closely.

Early DWI-MRI seems to play a major role in the prognostic evaluation of FSE in children. It may help to determine hippocampal involvement and assess the risk of subsequent HS. However, the study data are insufficient to conclude on the association between diffusion abnormalities and the development of MTLE. Although ASL perfusion may provide additional insight, more data are needed.