Related Experiment Video
Updated: Jun 16, 2026
Electromagnetic Source Imaging in Presurgical Evaluation of Children with Drug-Resistant Epilepsy
Published on: September 20, 2024
Contralateral hyperperfusion and ipsilateral hypoperfusion by ictal SPECT in patients with mesial temporal lobe
Jae-Wook Cho1, Seung Bong Hong, Jung Hwa Lee
1Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Abstract:
Ictal Single Proton Emission Computed Tomography (SPECT) has demonstrated high levels of sensitivity in localizing seizures among patients with epilepsy of the mesial temporal lobe (mTLE). However, incorrect information on the lateralization of mTLE has also been reported. In order to investigate the causes of these incorrect localizations, the authors assessed clinical symptoms, as well as the electroencephalography (EEG) and brain SPECT scan data of five patients with mTLE experiencing ictal hyperperfusion of the contralateral temporal lobe. All patients underwent presurgical evaluations, including an interictal and ictal brain SPECT scan. A subtraction ictal SPECT co-registered with Magnetic Resonance Imaging (MRI) procedure or SISCOM was performed. Hyperperfusion (ictal perfusion greater than interictal perfusion) and hypoperfusion (ictal perfusion lower than interictal perfusion), results of SISCOM were analyzed and compared with seizure and ictal EEG pattern patterns. All the five patients had unilateral hippocampal sclerosis, and the radiotracer for the ictal SPECT was injected after the ictal EEG pattern had propagated to the contralateral side. The average delay between the ictal EEG onset and the radiotracer injection was 29.7+/-9.6s. All hyperperfusion SISCOM results revealed hyperperfusion in the contralateral temporal region with a more intense ictal EEG build-up. However, hypoperfusion SISCOM results demonstrated significant hypoperfusion in the epileptogenic temporal lobe of three of the five patients, but no hypoperfusion finding in the other two patients. This study demonstrates that early ictal EEG pattern propagation to the contralateral side in mTLE may be associated with contralateral ictal hyperperfusion with or without ipsilateral temporal hypoperfusion. The authors recommend simultaneous interpretations of ictal SPECT and ictal EEG propagation patterns at the time of the injection of radiotracers.
Insights
Contralateral ictal hyperperfusion on SPECT scans in mesial temporal lobe epilepsy (mTLE) can occur when seizure activity spreads early. Simultaneous interpretation of SPECT and EEG is recommended for accurate localization.
Area of Science:
- Neuroscience
- Medical Imaging
- Epileptology
Background:
- Ictal Single Proton Emission Computed Tomography (SPECT) is sensitive for localizing mesial temporal lobe epilepsy (mTLE).
- However, inaccurate lateralization of mTLE has been reported, necessitating investigation into its causes.
Purpose of the Study:
- To investigate the causes of incorrect lateralization in mTLE using ictal SPECT.
- To analyze clinical symptoms, electroencephalography (EEG), and SPECT data in mTLE patients with contralateral temporal lobe hyperperfusion.
Main Methods:
- Assessed five mTLE patients with unilateral hippocampal sclerosis undergoing presurgical evaluation.
- Performed interictal and ictal brain SPECT scans, analyzed using subtraction ictal SPECT co-registered with MRI (SISCOM).
- Compared SISCOM results (hyperperfusion/hypoperfusion) with seizure and ictal EEG propagation patterns.
Main Results:
- All five patients showed contralateral temporal hyperperfusion on SISCOM, associated with contralateral ictal EEG spread.
- Three patients exhibited significant ipsilateral temporal hypoperfusion, while two did not.
- Radiotracer injection occurred with an average delay of 29.7 seconds after ictal EEG onset, coinciding with contralateral spread.
Conclusions:
- Early contralateral EEG propagation in mTLE can lead to contralateral ictal hyperperfusion, potentially with ipsilateral hypoperfusion.
- Simultaneous interpretation of ictal SPECT and ictal EEG propagation patterns is crucial for accurate localization in mTLE.
More Related Videos
10:22Interictal High Frequency Oscillations Detected with Simultaneous Magnetoencephalography and Electroencephalography as Biomarker of Pediatric Epilepsy
Published on: December 6, 2016
09:32Network Analysis of Foramen Ovale Electrode Recordings in Drug-resistant Temporal Lobe Epilepsy Patients
Published on: December 18, 2016