Brain magnetic resonance in status epilepticus: A focused review

PURPOSE Status epilepticus (SE) is a neurological emergency with multiple etiologies and a complex pathophysiology, which is incompletely understood. Brain magnetic resonance imaging (MRI) represents a noninvasive tool to increase our knowledge about epileptogenesis. This paper aims to review the main MRI findings in SE. METHOD We conducted a search in Medline database using the terms "MRI", "brain" and "status epilepticus" and further crossed for "diffusion-weighted image" (DWI), "perfusion", "spectroscopy", "susceptibility-weighted image" (SWI), "mortality", "morbidity" and "outcome". INCLUSION original articles written in English and selected case reports published from 1995 to 2015. Exclusion: reviews. RESULTS MRI may play a pivotal role in the disclosure of the etiology of SE, epileptic focus location and seizure propagation. Several techniques have been used. Concerning DWI, experimental models and clinical studies have complementary results. Periictal abnormalities may occur with cytotoxic and/or vasogenic edema involving both cortical and subcortical structures, but literature is controversial regarding their significance. DWI changes can be transient, but their maintenance could mean irreversible neuronal damage leading to focal brain atrophy and gliosis (mostly in the hippocampal region), possibly developing a new epileptic focus. Perfusion studies, including arterial spin labeling data, showed changes in cerebral blood flow. We also explore the possible vascular insight provided by SWI. CONCLUSION Ongoing imaging technical advances, particularly regarding MRI, may shed a light on SE pathophysiology and its structural or functional consequences, in a noninvasive way. Its findings may have implications in prognosis, potentially allowing the development of new and more individualized therapeutic.