Is Rolandic epilepsy associated with abnormal findings on cranial MRI?

Rolandic epilepsy (RE) is designated an idiopathic epilepsy syndrome, and hence no lesional abnormalities are expected on MRI exam. Recent reports suggest that MRI abnormalities are not only common, but may be specific for temporal lobe epilepsy, and lateralized to the side of EEG discharges. However, no controlled study has been performed to test the hypothesis of association between MRI abnormalities and Rolandic epilepsy. We performed an unmatched case-control study to test the hypothesis of association between MRI abnormalities and Rolandic epilepsy, using 25 typical RE cases and 25 children with migraine. Two independent examiners rated the MRIs for abnormalities. Examiners were blinded to the study hypothesis and identity of case and control exams. Fifty-two percent of RE exams contained at least one abnormality: peri/hippocampal abnormality (one case), non-localized congenital malformation (seven cases), subcortical parenchymal hyperintensities (two cases), periventricular parenchymal hyperintensities (one case), dilated perivascular spaces (six cases). There was no difference between the number or type of abnormalities in cases and controls. No type of abnormality lateralized to the hemisphere from which the EEG spikes emanated. The odds ratio of association between MRI abnormalities and RE was 0.87, 95% CI: 0.18-4.33 after adjusting for potential demographic and technical factors. We conclude that routine cranial MRI abnormalities are common in RE, but no more common than in controls, and not specific for RE.