The term epileptic seizure refers to a transient occurrence of signs and/or symptoms due to abnormally excessive neuronal activity of the cerebral cortex. Epilepsy is a condition characterized by recurrent, unprovoked seizures. The diagnosis of epilepsy is often not straightforward, and misdiagnosis is not rare . A detailed and reliable account of the event by an eyewitness is crucial to the diagnostic evaluation, but may not be available .
The purpose of the diagnostic evaluation in a patient with seizures is to provide evidence that helps confirm or refute the diagnosis of epilepsy and to identify the cause of epilepsy and/or to classify the epileptic syndrome. Neuroimaging also has a critical role in the evaluation of patients with refractory epilepsy for epilepsy surgery.
This topic will discuss neuroimaging in the diagnostic evaluation of adults with possible epileptic seizures. Other aspects of diagnostic testing for seizures and epilepsy are discussed separately. (See "Evaluation of the first seizure in adults" and "Clinical and laboratory diagnosis of seizures in infants and children" and "Electroencephalography (EEG) in the diagnosis of seizures and epilepsy" and "Video and ambulatory EEG monitoring in the diagnosis of seizures and epilepsy".)
Computed tomography (CT) is commonly ordered in patients presenting with new-onset seizure to an emergency department. It is generally available quickly in that setting and can exclude acute neurologic problems that require urgent intervention. (See "Evaluation of the first seizure in adults".)
However, in non-emergent situations, magnetic resonance imaging is more sensitive than CT and is the neuroimaging study of choice.