Neuroimaging of first-ever seizure: Contribution of MRI if CT is normal.

The role of neuroimaging in the assessment of a first-ever seizure has not been well-defined, in particular the utility of MRI when CT is normal. The results of neuroimaging (CT brain, MRI brain, or both) in 1,013 adults with first-ever unprovoked seizure were correlated with clinical features and seizure outcome. Epileptogenic lesions were identified in 29%. Of patients with a normal CT who also had MRI, 12% had an epileptogenic lesion on MRI, the strongest independent predictor of which was a focal abnormality on EEG. Patients with an epileptogenic lesion had a higher risk of seizure recurrence, including when this was only evident on MRI.