Reassessment: neuroimaging in the emergency patient presenting with seizure (an evidence-based review): report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.

OBJECTIVE To reassess the value of neuroimaging of the emergency patient presenting with seizure as a screening procedure for providing information that will change acute management, and to reassess clinical and historical features associated with an abnormal neuroimaging study in these patients. METHODS A broad-based panel with topic expertise evaluated the available evidence based on a structured literature review using a Medline search from 1966 until November 2004. RESULTS The 15 articles meeting criteria were Class II or III evidence since interpretation was not masked to the patient's clinical presentation; most were series including 22 to 875 patients. There is evidence that for adults with first seizure, cranial CT will change acute management in 9 to 17% of patients. CT in the emergency department for children presenting with first seizure will change acute management in approximately 3 to 8%. There is no clear difference between rates of abnormal emergent CT for patients with chronic seizures vs first. Children <6 months presenting with seizures have clinically relevant abnormalities on CT scans 50% of the time. Persons with AIDS and first seizure have high rates of abnormalities, and CNS toxoplasmosis is frequently found. Abnormal neurologic examination, predisposing history, or focal seizure onset are probably predictive of an abnormal CT study in this context. CONCLUSIONS Immediate noncontrast CT is possibly useful for emergency patients presenting with seizure to guide appropriate acute management especially where there is an abnormal neurologic examination, predisposing history, or focal seizure onset.