颅内电极三维重建在涉及脑功能区癫痫术前评估中的应用

The usefulness of 3-dimensional(3D) visualization of subdural electrodes for presurgical evaluation of epileptic patients Related to Eloquent Cortices

目的：探讨颅内电极三维重建在涉及脑功能区癫痫术前评估中的应用价值。方法：选择颅内电极植入术的难治性癫痫患者，术前MRI扫描重建脑组织的立体影像。骨瓣开颅电极植入，术中数码拍照，术后头颅cT扫描重建颅内电极。在颅内电极皮层脑电图监测期间，记录癫痫惯常发作起始区；通过慢性电刺激确定皮层功能区。运用图像融合软件将脑组织和颅内电极的三维图像进行融合，形成致痫区与脑功能区的立体虚拟影像。结果：本组共6例患者，男4例，女2例，颅内电极脑电图监测时间平均13．7d。通过影像三维重建．显示出硬脑膜下电极与其周边脑皮层的毗邻关系，解剖影像清晰，与术中数码照片有较高的一致性．将致痫灶与功能区标注到电极上后，可以显示致痫灶与功能区的空间分布。二期手术后随诊3～6个月．癫痫发作控制良好。结论：颅内电极三维重建能够清晰显示硬膜下电极与脑皮层的空间关系，有利于确定致痫灶与脑功能区的关系，在涉及脑功能区的癫痫术前评估中有较好的应用价值。

Objective Introduce a technique for creating 3-dimensional （3D） brain models of subdural electrodes, ideal for demonstrating the space-relationship of seizure localization and eloquent cortices, and discuss its usefulness for presurgical evaluation of epileptic patients. Methods Patients with medically intractable epilepsy were underwent a thorough preoperative MR brain scan including a Tl-weighted high- resolution 3D sequence. Intraoperative photographs were taken with the digital camera. After the surgical implantation of subdural electrodes for epileptic zone localization, the thin-slice CT scan of the electrodes were taken and coregistered to preoperative brain 3D MR images in the Medtronic StealthMerge software environment. After the iEEG monitoring, multiple habitual seizures were recorded, eloquent areas were also identified by electrical stimulation of the cortex. The epileptic zone and the eloquent areas were marked on the subdural electrodes respectively. Then, 3D tessellations of the epileptic zone and the eloquent areas were rendered. Results Six patients （4 male, 2 female） were enrolled in this study. The mean time of iEEG monitoring was 13.7 days. After the coregistration of postoperative CT with preoperative 3D MRI, the 3D stereoscopic reconstruction provided an accurate representation of the implanted electrodes with highly detailed visualization of the underlying anatomy. The visual comparison between 3D reconstructions and intraoperative photographs indicated a good correspondence. The patients were followed for 3 to 6 months after the secondary operation, and had continuing improvement in seizure control. Conclusions The results indicate that the 3D reconstruction of subdural electrodes can reveal the precise localization of subdural electrodes, and can be useful for the presurgical evaluation of epileptic patients.