Bittar R G, Andermann F, Olivier A, Dubeau F, Dumoulin S O, Pike G B, Reutens D C
Montreal Neurological Institute and Hospital, and Department of Neurology and Neurosurgery, McGill University, Quebec, Canada.
Epilepsia. 1999 Feb;40(2):170-8. doi: 10.1111/j.1528-1157.1999.tb02071.x.
In patients with reflex epilepsy, it is sometimes possible to evoke interictal spikes predictably, thus providing an uncommon but important experimental paradigm for examining the physiological changes produced by epileptiform discharges.
To examine the changes in regional cerebral blood flow (rCBF) and glucose consumption (rCMRglc) produced by interictal spikes, we performed positron emission tomography (PET) scans with the blood-flow tracer [15O]H20 and with [18F]fluorodeoxyglucose in a patient with fixation-off epilepsy. The scans were performed in states of high and low spike frequency produced by eye closure and opening, respectively.
The rCBF study revealed a focal increase in blood flow associated with the state of increased interictal spiking. The focus was in the posterior portion of the left superior parietal lobule (Talairach coordinates: x: -36, y: -71, z: 39; t = 4.5; p<0.05) and corresponded to the site of maximal ictal EEG abnormality recorded with implanted electrodes. In a volume of interest of 10-mm diameter centered on the t statistic peak in the rCBF study, the mean rCMRglc was 39.1 micromol/100 g/min with eyes open and 44.1 micromol/100 g/min (13% increase) with eyes closed. An identical activation paradigm was used in six normal subjects studied with functional magnetic resonance imaging. In the normal subjects, no significant activation was observed in the parieto-occipital region, indicating that the changes observed in the patient were due to interictal spiking rather than to task performance alone.
Interictal spiking produces focal increases in cerebral blood flow and glucose metabolism.
在反射性癫痫患者中，有时可以可预测地诱发发作间期棘波，从而为研究癫痫样放电所产生的生理变化提供了一种罕见但重要的实验范例。
为了研究发作间期棘波所产生的局部脑血流（rCBF）和葡萄糖代谢（rCMRglc）的变化，我们对一名光敏感性癫痫患者进行了正电子发射断层扫描（PET），分别使用血流示踪剂[15O]H2O和[18F]氟脱氧葡萄糖进行扫描。扫描分别在闭眼和睁眼产生的高棘波频率和低棘波频率状态下进行。
rCBF研究显示，与发作间期棘波增加状态相关的血流局部增加。该焦点位于左侧顶上小叶后部（Talairach坐标：x：-36，y：-71，z：39；t = 4.5；p<0.05），并且与植入电极记录到的最大发作期脑电图异常部位相对应。在rCBF研究中以t统计峰值为中心的直径10毫米的感兴趣体积内，睁眼时平均rCMRglc为39.1微摩尔/100克/分钟，闭眼时为44.1微摩尔/100克/分钟（增加13%）。在六名使用功能磁共振成像研究的正常受试者中使用了相同的激活范例。在正常受试者中，顶枕区未观察到明显激活，表明在该患者中观察到的变化是由于发作间期棘波，而不仅仅是由于任务执行。
发作间期棘波导致脑血流和葡萄糖代谢的局部增加。
