Magnetic Resonance Imaging after Seizures in Patients with an Ischemic Stroke

Background: Seizures related to ischemic strokes are harmful. Their pathogenesis is not very well understood. The present study investigates whether diffusion-weighted imaging (DWI) can detect if those seizures are due to recurrent infarction or responsible for secondary ischemic changes. Patients and Methods: DWI was obtained within 8 days in 60 patients with seizures (7 early and 53 late onset) related to an ischemic stroke. Results: In 30 patients, positive DWI with decreased apparent diffusion coefficient was found. In 11 patients with late-onset seizures, the DWI showed a positive rim, surrounding the old infarct, while in 12 patients a large positive zone corresponding to a new infarct was observed. All 7 patients with early-onset seizures had positive DWI corresponding to the establishing infarct. A large positive zone on DWI was mainly observed in cardioembolic stroke. Conclusions: The positive rim around the old infarct can be considered as cytotoxic edema. Recurrent acute infarction, mainly of cardioembolic origin, seems to be a significant cause of so-called late-onset seizures, making the subdivision into early- and late-onset seizures arbitrary.