Periictal SPECT localization verified by simultaneous intracranial EEG

Area of Science:

• Neurology
• Medical Imaging
• Epileptology

Background:

• Accurate localization of epileptic seizure origins is crucial for effective treatment planning in epilepsy.
• Single photon emission computed tomography (SPECT) is a neuroimaging technique used to assess brain perfusion.

Purpose of the Study:

• To determine if blood-flow changes measured by ictal or immediate postictal SPECT accurately reflect the location of ictal discharge identified by intracranial electroencephalography (EEG).
• To evaluate the reliability of ictal SPECT performed during invasive monitoring by comparing it with results from scalp EEG monitoring.

Main Methods:

• Eleven patients with intractable partial epilepsy underwent ictal and interictal SPECT scans during invasive EEG monitoring.
• Perfusion differences were analyzed using registered, normalized, and subtracted SPECT images.
• SPECT results were correlated with the location and evolution of ictal EEG changes.

Main Results:

• In 10 out of 11 patients, localized blood flow increases or decreases were observed in regions corresponding to ongoing or prior seizure discharge during SPECT.
• SPECT localization was verifiable in most patients, correlating with EEG findings.

Conclusions:

• Ictal SPECT accurately identifies the region of epileptic discharge by detecting changes in brain perfusion.
• Both increases and decreases in perfusion during or before SPECT injection are equally valid indicators of epileptic discharge location.
• Reliable ictal SPECT data can be obtained during intracranial EEG monitoring.