When diagnosing epilepsy, special imaging tests may be needed to supplement the findings from the neurological exam and EEG recordings. Brain imaging can help pinpoint the areas of the brain causing the seizures.
Magnetic imaging resonance (MRI), positron emission tomography (PET), and single photon emission tomography (SPECT) can supplement findings from video EEG and routine EEG.
MRI can reveal structural brain abnormalities causing seizures. In general, MRI takes a picture showing the brain anatomy, which can sometimes be abnormal in patients with epileptic seizures.
Typical clinical PET allows detection of brain areas with abnormal glucose metabolism. Epileptic seizures can be related to brain regions of abnormal metabolism of glucose, so these areas are sometimes indicators of where seizures are developing.
Typical clinical SPECT studies measure brain blood flow and perfusion. Because blood flow to the brain is most altered during the seizures, SPECT is often done during the seizure itself, and is referred to as ictal SPECT.
About SPECT - Single Photon Emission Tomography
SPECT done during a seizure increases the ability to identify the exact location from which seizures start in the brain. During video EEG monitoring, nurses or EEG technologists administer an intravenous injection of a blood flow tracer. After the tracer is injected, it will stay in the brain for several hours. Patients are then taken from the video EEG monitoring unit to undergo a SPECT scan.
Typically, another SPECT scan is obtained in between seizures so that the blood flow changes both during and in between seizures can be compared. Findings from the SPECT studies allow neurologists and radiologists to track sometimes subtle changes in blood flow in the area of seizure onset. By combining that data with the EEG readings, physicians can trace the extended blood flow patterns that identify seizure pathways.
Because video EEG telemetry monitoring is necessary during ictal SPECT studies, all ictal SPECT studies are performed in the hospital in an inpatient setting.
For a referral to a Washington University neurologist or neurosurgeon at Barnes-Jewish Hospital, call