Magnetoencephalography-directed surgery in patients with neocortical epilepsy
Magnetoencephalography-directed surgery in patients with neocortical epilepsy
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DOI：
10.3171/jns.2002.97.4.0865
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发表时间：
2002-10-01
影响因子：
4.1
通讯作者：
Sutherling, WW
中科院分区：
文献类型：
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作者：
Mamelak, AN;Lopez, N;Sutherling, WW
对象。脑磁图（MEG）和磁源（MS）成像技术已越来越多地用于术前定位癫痫灶和雄辩皮层区域。MEG检查的使用必须仔细权衡进行这些研究所需的高成本和技术投资，特别是当有更便宜的替代定位方法可用时。为了帮助阐明脑磁图的价值，作者回顾了他们在癫痫手术患者的病例管理中使用全头部脑磁图的经验。作者确定了1-3例疑似局灶性癫痫的患者，他们在亨廷顿纪念医院接受了全头部MEG和MS成像，随后进行了侵入性颅内电极监测和皮质电图（ECoG），以定位癫痫发作区域，以便进行手术切除。根据在4小时的记录过程中记录的间隔尖峰的数量，将MS成像结果回顾性地分为三组：I类（无尖峰），II类（小于或等于5个尖峰）和III类（大于或等于6个尖峰）。根据间隔尖峰的聚集密度进一步细分为III类：IIIA类表示间隔尖峰之间的平均距离大于等于4mm（即弥散聚集），IIIB类表示间隔尖峰之间的平均距离小于4mm（即密集聚集）。作者分析了这些组，以确定在多大程度上MS成像结果与脑电图确定的癫痫发作起源区相关。此外，他们评估了MS成像研究是否提供了关键的定位数据，并与切除后的手术结果相关。还对这些相关性进行了统计分析。在研究的40例患者中，23例接受了有创监测，其中13例为新皮质癫痫，4例为内侧颞叶癫痫，6例疑似新皮质癫痫，ECoG无法明确定位。深度电极9例，硬膜下网格9例，深度电极加硬膜下网格和条带4例，术中ECoG 1例。在23例患者中，有16例（70%）能够定位癫痫发作区。在ECoG能够定位癫痫发作起始区域的16例病例中，有11例（69%）的MS图像间歇峰被归类为IIIB类（密集聚集），并且在所有病例中与MS成像确定的定位（即同一叶）区域相关，相反，当ECoG无法定位癫痫发作起始区域时，没有识别出IIIB类病例。这种差异有统计学意义（p < 0.23）的趋势，但没有达到统计学意义（p < 0.23），可能是因为可供分析的病例数量相对较少。在3例病例（均为IIIB级）中，MS成像用于引导侵入性电极到达否则无法定位的位置，并提供了独特的定位数据，这在其他成像方式中是不明显的，这对患者的手术治疗有很大影响。将MS图像上的发现分类为亚组，随后进行统计分析，得出一个模型，预测IIIB类MS成像数据可能提供可靠的信息来指导手术电极的放置，但所有其他数据组都不能提供足够可靠的定位信息来指导手术决策。磁源成像可以提供其他非侵入性方法无法提供的独特定位信息。磁源成像对新皮质性癫痫最有用。特别是，当MS成像研究显示六个或更多的间隔尖峰密集聚集在一个解剖位置时，MS图像与ECoG识别的癫痫发作起源区域高度相关。在这些病例中，MS成像数据可能有助于指导颅内电极的放置。
Object. Magnetoencephalography (MEG) and magnetic source (MS) imaging are techniques that have been increasingly used for preoperative localization of epileptic foci and areas of eloquent cortex. The use of MEG examinations must be carefully balanced against the high cost and technological investments required to perform these studies, particularly when less expensive alternative localization methods are available. To help elucidate the value of MEG, the authors have critically reviewed their experience with whole-head MEG in the case management of patients undergoing epilepsy surgery.Methods. The authors identified 1-3 patients with suspected focal epilepsy who underwent whole-head MEG and MS imaging at Huntington Memorial Hospital and, subsequently, underwent invasive intracranial electrode monitoring and electrocorticography (ECoG) to localize the zone of seizure origin for surgical resection. The results of the MS imaging were retrospectively stratified into three groups by the number of interictal spikes recorded during a 4-hour recording session: Class I (no spikes), Class II (less than or equal to five spikes), and Class III (greater than or equal to six spikes). Class III was further subdivided according to the clustering density of the interictal spikes: Class IIIA represents a mean distance between interictal spikes of 4 mm or greater (that is, diffusely clustered) and Class IIIB represents a mean distance between interictal spikes of less than 4 mm (that is, densely clustered). The authors analyzed these groups to determine to what extent the results of MS imaging correlated with the ECoG-determined zone of seizure origin. In addition, they assessed whether the MS imaging study provided critical localization data and correlated with surgical outcome following resection. A statistical analysis of these correlations was also performed.Of the 40 patients studied, 23 underwent invasive monitoring, including 13 with neocortical epilepsy, four with mesial temporal lobe epilepsy, and six with suspected neocortical epilepsy that could not be clearly localized by ECoG. Depth electrodes were used in nine cases, subdural grids in nine cases, depth electrodes followed by subdural grids and strips in four cases, and intraoperative ECoG in one case. Electrocorticography was able to localize the zone of seizure origin in 16 (70%) of 23 cases. In 11 (69%) of the 16 cases in which ECoG was able to localize the zone of seizure origin, the interictal spikes on the MS images were classified as Class IIIB (densely clustered) and regionally correlated to the MS imaging-determined localization in all cases (that is, the same lobe), In contrast, no Class IIIB cases were identified when ECoG was unable to localize the zone of seizure origin. This difference showed a trend toward, but did not achieve, statistical significance (p < 0.23), presumably because of the relatively small number of cases available for analysis. In three cases (all Class IIIB), MS imaging was used to guide invasive electrodes to locations that otherwise Would not have been targeted and provided unique localization data, not evident from other imaging modalities, that strongly influenced the surgical management of the patient. The classification of findings on MS images into subgroups and subsequent statistical analysis generated a model that predicted that Class IIIB MS imaging data are likely to provide reliable information to guide surgical placement of electrodes, but all other data groups do not provide localization information that is reliable enough to guide surgical decision making.Conclusions. Magnetic source imaging can provide unique localization information that is not available when other noninvasive methods are used. Magnetic source imaging appears most useful for cases of neocortical epilepsy. In particular, when an MS imaging study revealed six or more interictal spikes that were densely clustered in a single anatomical location, the MS image was highly correlated with the zone of seizure origin identified by ECoG. In these cases the MS imaging data may be useful to guide placement of intracranial electrodes.