Hyperdensity on CT after seizure: a pitfall

A 12-year-old boy had a hyperdense area corresponding to a gyral pattern on an enhanced CT brain scan within 12 hours of his last seizure. The hyperdense area disappeared on a subsequent enhanced CT scan after he was seizure free for about 48 hours. The hyperdense area was in a location (mesial frontal lobe) predicted by the interictal physical exam findings and the seizure type recorded on video-EEG monitoring. We postulate that the CT abnormality was due to transitory increase of regional cerebral blood flow and vascular permeability.