Imai K, Otsubo H, Sell E, Mohamed I, Ochi A, RamachandranNair R, Snead O C
Division of Neurology, The Hospital for Sick Children, Toronto, Canada.
Acta Neurol Scand. 2007 Oct;116(4):263-7. doi: 10.1111/j.1600-0404.2007.00866.x.
A child whose left temporal lobe contained mesial, anterior and basal structures but lacked superio-lateral cortex had intractable epilepsy secondary to a porencephalic cyst. Magnetoencephalography (MEG) shows equivalent current dipoles (ECDs) as dipole modeling for temporal lobe epilepsy rather than in an exact location.
We hypothesized that the magnetic fields generated by the epileptic discharges in mesio-basal temporal areas could be detected by MEG without interference from the superio-lateral temporal cortices.
We analyzed MEG spikes using single dipole analysis and synthetic aperture magnetometry (SAM), and compared with EEG spike topography.
Two MEG ECDs corresponding to T3 spikes localized to the anterior mesio-basal temporal region with vertical orientation. Sixteen MEG ECDs corresponding to T5 spikes localized to the middle to posterior mesio-basal temporal region with vertical orientation. SAM revealed maximum current density at hippocampus and anterior fusiform gyrus for T3 spikes, and at posterior hippocampus and fusiform gyrus for T5 spikes.
Vertically oriented ECDs were obtained without superio-lateral temporal cortices because of temporo-parieto-occipital porencephalic cyst. The absence of superio-lateral temporal cortices, prominent temporal EEG spikes, less prominent MEG spikes, and mesio-basal SAM spikes indicated that the vertically oriented ECDs were projected directly from the mesio-basal temporal region.
一名儿童左颞叶包含内侧、前部和基底结构，但缺乏颞上外侧皮质，患有脑穿通性囊肿继发的难治性癫痫。脑磁图（MEG）显示等效电流偶极子（ECD）作为颞叶癫痫的偶极子模型，而非位于精确位置。
我们假设MEG能够检测到内侧基底颞叶区域癫痫放电产生的磁场，而不受颞上外侧皮质的干扰。
我们使用单偶极子分析和合成孔径磁ometry（SAM）分析MEG棘波，并与脑电图棘波地形图进行比较。
两个与T3棘波对应的MEG ECD定位于前内侧基底颞叶区域，呈垂直方向。16个与T5棘波对应的MEG ECD定位于中后内侧基底颞叶区域，呈垂直方向。SAM显示T3棘波在海马体和前梭状回处电流密度最大，T5棘波在海马体后部和梭状回处电流密度最大。
由于颞顶枕脑穿通性囊肿，在没有颞上外侧皮质的情况下获得了垂直方向的ECD。颞上外侧皮质的缺失、明显的颞叶脑电图棘波、不太明显的MEG棘波以及内侧基底SAM棘波表明垂直方向的ECD直接从内侧基底颞叶区域投射而来。
