Will MRI replace the EEG for the diagnosis of nonconvulsive status epilepticus, especially focal?

Magnetic resonance imaging (MRI) can now be used to diagnose or to provide confirmation of focal nonconvulsive status epilepticus (NCSE). Approximately half of patients with status epilepticus (SE) have signal changes. MRI can also aid in the differential diagnosis with generalized NCSE when there is a clinical or EEG doubt, e.g. with metabolic/toxic encephalopathies or Creutzfeldt-Jakob disease. With the development of stroke centers, MRI is available 24 h/24 in most hospitals. MRI has a higher spatial resolution than electroence-phalography (EEG). MRI with hyperintense lesions on FLAIR and DWI provides information related to brain activity over a longer period of time than a standard EEG where only controversial patterns like lateralized periodic discharges (LPDs) may be recorded. MRI may help identify the ictal nature of LPDs. The interpretation of EEG tracings is not easy, with numerous pitfalls and artifacts. Continuous video-EEGs require a specialized neurophysiology unit. The learning curve for MRI is better than for EEG. It is now easy to transfer MRI to a platform with expertise. MRI is more accessible than single photon emission computed tomography (SPECT) or positron emission tomography (PET). For the future, it is more interesting to develop a strategy with MRI than SPECT or PET for the diagnosis of NCSE. With the development of artificial intelligence, MRI has the potential to transform the diagnosis of SE. Additional MRI criteria beyond the classical clinical/EEG criteria of NCSE (rhythmic versus periodic, spatiotemporal evolution of the pattern...) should now be systematically added. However, it is more complicated to move patients to MRI than to perform an EEG in the intensive care unit, and at this time, we do not know how long the signal changes persist after the end of the SE. Studies with MRI at fixed intervals and after SE cessation are necessary. (C) 2021 Elsevier Masson SAS. All rights reserved.