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

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.