The diagnostic assessment of single seizures. Is cranial computed tomography necessary?

To determine the usefulness of cranial computed tomography (CCT) in adults with a single seizure, we prospectively examined 62 such patients who were initially seen within 24 hours of the event. Age range was 16 to 86 years. Seizure was partial in ten patients and generalized in 52. Neurologic examination results were abnormal in 28 and normal in 34. Laboratory studies, including EEG and CCT, were completed within the subsequent 24 hours. In 29 patients, CCT was abnormal. Only nine of them had normal neurologic examination results, and only four also had a normal EEG. In these, generalized atrophy was the only CCT abnormality. None of the nine occurred in patients aged 16 to 30 years. We concluded that CCT is not essential for patients aged 16 to 30 years who have normal examination results. In patients aged 31 years or older with normal examination results and normal EEG, CCT may be abnormal but is unlikely to provide essential information. Irrespective of age or seizure type, CCT is useful and essential in patients with abnormal neurologic examination results.