Ictal SPECT With Intra-arterial Injection
Ictal SPECT With Intra-arterial Injection
Ictal SPECT with intravenous injection in a cubital vein of a perfusion tracer is an
 established technique to localize the ictal onset zone during presurgical evaluation of
 refractory focal epilepsy. When seizures last less than 10 seconds, localizing information is
 often not obtained. Since it takes around 30 seconds before the tracer reaches the brain
 after intravenous injection, ictal hyperperfusion most likely has already switched to
 postictal hypoperfusion. In this study, we plan to inject the perfusion tracer in the aorta
 proximal to the cerebral arteries, which will allow a true ictal injection in patients with
 seizures of short duration.
In this study, the investigators will select one patient with refractory focal epilepsy with
 frequent seizures of short duration, which can not be localized with early ictal SPECT with
 intravenous injection in a cubital vein. An arterial catheter will be inserted. The right
 groin will be disinfected using an alcoholic disinfectant and locally anaesthetized. The
 artery in the groin, the femoral artery, will be punctured. A catheter is inserted in the
 artery and slided towards the heart. To determine the correct position of the catheter
 proximal to the cerebral arteries, a contrast agent will be injected, and at the same time
 radiographs will be taken. The catheter will be attached and taped in the groin. The patient
 will be monitored with video-EEG recording. During an epileptic seizure, the perfusion tracer
 99m-Technetium Ethyl Cysteinate Dimer (99mTc- ECD) dissolved in 30 cc normal saline will be
 injected with a pressure injector over 2 seconds. After injection, the catheter will be
 removed and the ictal SPECT scan will be performed. Subtracted ictal SPECT images
 co-registered with MRI (SISCOM) will be obtained. The investigators plan to do this study in
 one patient in order to assess whether this procedure is logistically possible and to
 determine whether subtraction images of ictal SPECT with intra-arterial injection minus
 interictal SPECT with intravenous injection allows localization of the ictal onset zone.
Inclusion Criteria:

 -  Refractory unifocal epilepsy

 -  Early ictal SPECT with intravenous injection did not localize the ictal onset zone

 -  Several seizure per day, or clusters of several seizures per day

 -  Seizures are of short duration (i.e. less than 10-15 seconds)

 -  Patient asks for epilepsy surgery

 Exclusion Criteria:

 -  Renal failure

 -  Allergy to contrast agents

 -  Fever

 -  Anemia

 -  Usage of anticoagulants

 -  Pregnancy