Department of Neurology and Neurosurgery, Comprehensive Epilepsy Center, Feinstein Institute for Medical Research, North Shore LIJ Health System, New Hyde Park, NY 11040, United States.
Epilepsy Res. 2010 Mar;89(1):126-32. doi: 10.1016/j.eplepsyres.2009.12.001. Epub 2010 Mar 7.
Functional magnetic resonance imaging (fMRI) is commonly used to localize brain function, but its utility in the clinical setting remains unclear. Subdural electrode implantation provides opportunities to correlate the spatial relationship of the blood oxygen level-dependent (BOLD) response to areas defined by extraoperative electrical stimulation mapping (ESM) in patients undergoing staged epilepsy surgery. 4 subjects underwent pre-operative fMRI using the analogous paradigms to those used for ESM to delineate language and motor function. Coregistration of the pre-operative MRI to a post-operative CT and MRI scan was performed in order to assess the spatial relationship between the BOLD response and the location of electrode contacts used for ESM while accounting for brain shift. fMRI was accurate in predicting the location of motor cortex with sensitivity and negative predictive value (NPV) of 1.0. Specificity was .96 with a positive predictive (PPV) value of .8. In all 4 subjects, a laterality index of the fMRI for language was accurate in predicting lateralization measured by Wada testing. While T-scores over regions where ESM-induced language deficits occurred were significantly higher (p<.05, Student's t-test) than those over regions where there was no ESM-induced deficit, sensitivity, specificity and predictive values were poor over a range of threshold criteria. Sensitivity and specificity were improved by excluding sites within 1cm of the base of the frontal and temporal bone and sites where ESM showed motor function of face. Despite this, sensitivity and specificity were .47 and .76, respectively (T score 2.5, p<.01 corrected FDR) with PPV and NPV of .40 and .77, respectively. Sensitivity for predicting areas within 1cm of ESM-defined language sites was higher at .82 with an NPV of .94. The results indicate that fMRI is clinically useful for lateralizing language and the localizing motor cortex. fMRI localizes language less accurately, but it may be useful in estimating the region of ESM-induced deficit in areas away from the base of the frontal and temporal bone.
功能磁共振成像（fMRI）常用于定位脑功能，但在临床环境中的应用尚不清楚。硬膜下电极植入为在接受分期癫痫手术的患者中，将血氧水平依赖（BOLD）反应的空间关系与手术中电刺激映射（ESM）定义的区域相关联提供了机会。4 名受试者在术前使用与 ESM 类似的范式进行 fMRI，以描绘语言和运动功能。为了评估 BOLD 反应与用于 ESM 的电极接触位置之间的空间关系，同时考虑到脑移位，对术前 MRI 与术后 CT 和 MRI 扫描进行了配准。fMRI 能够准确预测运动皮层的位置，其敏感性和阴性预测值（NPV）均为 1.0。特异性为 0.96，阳性预测值（PPV）为 0.8。在所有 4 名受试者中，语言 fMRI 的侧偏指数准确预测了通过 Wada 测试测量的侧化。虽然 T 分数在 ESM 引起语言缺陷的区域明显高于（p<.05，Student's t 检验）在没有 ESM 引起缺陷的区域，但在一系列阈值标准下，敏感性、特异性和预测值均较差。通过排除额骨和颞骨基部 1cm 内的部位以及 ESM 显示面部运动功能的部位，可提高敏感性和特异性。尽管如此，敏感性和特异性分别为 0.47 和 0.76（T 分数 2.5，p<.01 校正 FDR），PPV 和 NPV 分别为 0.40 和 0.77。预测 ESM 定义的语言部位 1cm 内区域的敏感性更高，为 0.82，NPV 为 0.94。结果表明，fMRI 对于语言的侧化和运动皮层的定位具有临床意义。fMRI 定位语言的准确性较低，但它可能有助于估计远离额骨和颞骨基部的 ESM 诱导的缺陷区域。
