A wide spectrum of variably periictal MRI abnormalities induced by a single or a cluster of seizures

Abstract

Background: Although predominantly reported in patients with status epilepticus, periictal MRI abnormalities have been reported in patients with a single or a cluster of seizures. Clinicians are often presented with a dilemma concerning the features of MRI abnormalities induced by a single or a cluster of seizures, as they may represent the effect of seizure activity rather than its structural cause.

Methods: A retrospective review of clinical and neuroimaging charts of 14 patients diagnosed with a single or a cluster of seizure-related MR-signal changes from the database of our unit (approximately 300 patients diagnosed with a single or a cluster of seizures underwent brain-MRI within 14 days from a seizure) was conducted. Extensive clinical work-up and follow-up, ranging from 3 months to 5 years, ruled out infection or other possible causes of brain damage. Site, characteristics and reversibility of MRI changes, and association with characteristics of seizures were determined.

Results: MRI showed unilateral abnormalities in 14 patients, with hyperintensities on T2-signal (12/14), fluid-attenuated inversion-recovery (FLAIR) (12/14), and restricted diffusion (6/8). Location of abnormality was cortical (4/14), subcortical (6/14), thalamus (2/14), corpus callosum (1/14), and bordering an old encephaloclastic lesion (1/14). Periictal MRI abnormalities and electroclinical findings in 10 patients showed an almost complete topographic concordance, which was not consistent in 4 patients. Reversibility of MRI changes was complete in 11 patients, partially disappeared in 1 patient, and irreversible on MRI in 2 patients.

Conclusions: A single or a cluster of seizures cannot only induce transient, variably reversible MRI brain abnormalities, but also irreversible changes. These seizure-induced MRI abnormalities pose a broad differential diagnosis; increased awareness may reduce the risk of misdiagnosis and unnecessary intervention.

Keywords: Cluster of seizures; Differential diagnosis; MRI; Periictal MRI abnormalities; Seizure; Status epilepticus.