Peri-ictal magnetic resonance imaging abnormalities during status epilepticus in adults with idiopathic generalized epilepsy

OBJECTIVE: Peri-ictal abnormalities on diffusion-weighted magnetic resonance imaging (DWI-PMA) are well established in patients with status epilepticus (SE). SE occurs in approximately 4-9% of patients with idiopathic generalized epilepsy (IGE), and outcomes are generally more favorable than in SE due to other causes. We investigated whether the rate of DWI-PMA differs between SE associated with IGE and SE due to other etiologies. METHODS: We performed a systematic review and individual patient meta-analysis of all studies published up to January 27th, 2025, reporting adult patients with non-anoxic SE and data on DWI-PMA. RESULTS: A total of 4,227 studies were screened, of which 185 met eligibility criteria (134 single case reports, 32 cohort studies, and 19 conference abstracts). Individual patient data were available for 531 patients from 17 studies. In addition, cumulative data from 326 patients with reported DWI-PMAs were available from 15 further studies. Among 38 patients with IGE who underwent peri-ictal MRI, none demonstrated DWI-PMAs associated with typical absence status or convulsive SE (estimated rate of 0%; one-sided 95% Clopper-Pearson confidence interval: 0%-10.0%). In contrast, 26.8% of patients with focal SE had DWI-PMAs (two-sided 95% Clopper-Pearson confidence interval: 24.8%-28.9%, p < 0.001, Fisher's exact test). Sensitivity analyses showed no major deviation from the expected prevalence of IGE based on population-based cohorts. CONCLUSION: SE associated with IGE is linked to a substantially lower risk of DWI-PMA as compared to SE due to other causes.