[P2-69] Magnetoencephalographic analysis of ictal discharges using dynamic statistical parametric mapping
[Introduction]
The aim of this study was to investigate pathophysiology of ictal discharges in children with epilepsy by a magnetoencephalography (MEG) with dynamic statistical parametric mapping (dSPM) analysis.
[Methodology]
Participants were four children with ictal MEG records. The hole-head MEG signals were analyzed by dSPM analysis that enabled to extract brain areas with higher currents during ictal attack, compared to the background brain activity. The brain areas estimated by dSPM were superimposed on magnetic resonance images (MRI). The results obtained by dSPM were also compared with equivalent current dipole (ECD) estimation, 99mTc-ECD-SPECT, and 18F-FDG-PET.
[Results]
Patient-1 showed no lesion on MRI, but decrement of perfusion and metabolism on 99mTc-ECD-SPECT and 18F-FDG-PET during inter-ictal period in bilateral frontal lobe. The ECDs were clustered around bilateral mesial frontal lobes. The dSPM revealed first high magnetic fields in the right nucleus accumbens followed by propagation to the right temporal lobe. Patient-2 had no finding on MRI, 99mTc-ECD-SPECT, and 18F-FDG-PET. The ECDs were located in right parietal lobe, and dSPM showed significant magnetic fields at the same area. Patient-3 had no lesion on MRI and 99mTc-ECD-SPECT. The ECD analysis was not successful, but dSPM showed simultaneous increment of magnetic fields in bilateral frontal pole with propagation to bilateral parietal lobe. Patient-4 showed abnormal enlargement of amygdala on MRI. The ECD and dSPM analyses were not successful.
[Conclusions]
Analysis of ictal MEG with dSPM showed an advantage to identify origins and propagation of the epileptic discharges, especially in patients with epileptogenic lesions in neocortices.
The aim of this study was to investigate pathophysiology of ictal discharges in children with epilepsy by a magnetoencephalography (MEG) with dynamic statistical parametric mapping (dSPM) analysis.
[Methodology]
Participants were four children with ictal MEG records. The hole-head MEG signals were analyzed by dSPM analysis that enabled to extract brain areas with higher currents during ictal attack, compared to the background brain activity. The brain areas estimated by dSPM were superimposed on magnetic resonance images (MRI). The results obtained by dSPM were also compared with equivalent current dipole (ECD) estimation, 99mTc-ECD-SPECT, and 18F-FDG-PET.
[Results]
Patient-1 showed no lesion on MRI, but decrement of perfusion and metabolism on 99mTc-ECD-SPECT and 18F-FDG-PET during inter-ictal period in bilateral frontal lobe. The ECDs were clustered around bilateral mesial frontal lobes. The dSPM revealed first high magnetic fields in the right nucleus accumbens followed by propagation to the right temporal lobe. Patient-2 had no finding on MRI, 99mTc-ECD-SPECT, and 18F-FDG-PET. The ECDs were located in right parietal lobe, and dSPM showed significant magnetic fields at the same area. Patient-3 had no lesion on MRI and 99mTc-ECD-SPECT. The ECD analysis was not successful, but dSPM showed simultaneous increment of magnetic fields in bilateral frontal pole with propagation to bilateral parietal lobe. Patient-4 showed abnormal enlargement of amygdala on MRI. The ECD and dSPM analyses were not successful.
[Conclusions]
Analysis of ictal MEG with dSPM showed an advantage to identify origins and propagation of the epileptic discharges, especially in patients with epileptogenic lesions in neocortices.