功能磁共振成像定位皮质运动区与术中电刺激运动诱发电位的前瞻对照研究

目的以术中电刺激运动诱发电位（MEP）监测为对照,评价中央区脑肿瘤术前运用血液氧饱和水平检测（BOLD）技术的功能磁共振成像（fMRI）定位皮质运动区的准确性。方法此项前瞻性研究选取了16例中央区脑肿瘤。开颅手术前分别执行手运动激发程式,运用BOLD技术的fMRI定位皮质运动区。将fMRI影像与磁共振导航序列影像融合。以术中MEP监测作为皮质运动区定位的标准技术。在神经导航下定位fMRI的各个激活区,单独或联合运用短串经颅电刺激（TCES）和直接皮质电刺激（DCES）,在前臂及手部记录复合肌肉动作电位。比较两种技术的吻合度,以评价fMRI定位的皮质运动区的准确性。结果fMRI与MEP的吻合率为92．3％,其中与TCES的吻合率为100．0％,与DCES的吻合率为66．7％。结论运用BOLD技术的fMRI敏感度高,可实现中央区脑肿瘤术前皮质运动区的准确定位。

Prospective comparison of functional magnetic resonance imaging and intraoperative motor evoked potential monitoring for cortical mapping of primary motor areas

Objective To compare the relation between the preoperative functional magnetic resonance imaging(fMRI) with blood oxygen level dependent(BOLD) technique and intraoperative motor evoked potential(MEP) monitoring for cortical mapping of primary motor cortex in patients with tumors near the central area.And to determine whether non-invasive preoperative fMRI can provide results equivalent to those achieved with the invasive neurosurgical "gold standard".Methods A prospective study of 16 patients with various pathological tumors of the central area was conducted.Preoperative fMRI scans using the BOLD contrast technique in each patient were performed.An activation scan was achieved by using a motor task paradigm,which consisted of simple flexion-extension finger movements and finger-to-thumb touching in a repeating pattern.The anatomical structure was delineated by the T_1-weighted three-dimensional fast spoiled gradient recalled sequence(3D/FSPGR) immediately afterward. The BOLD images were overlaid on the T_1-weighted 3D/FSPGR images,and then co-registered to the neuronavigation system.The fMRI activations were documented by using a neuronavigation system in sequence,and compared to standardized intraoperative MEP monitoring,which included direct cortical electrical stimulation(DCES) or transcranial cortical electrical stimulation(TCES) or their combination.The compound muscle action potentials of forearm flexor and hand muscle responses were recorded during either TCES or DCES.Two techniques were compared to determine the accuracy for cortical mapping of primary motor areas with fMRI. Results Overall,the intraoperative MEP monitoring showed good correlation with fMRI activation in 92.3% of cases.The coincidence rate,however,was 100.0% between TCES and fMRI,and 66.7% between DCES and fMRI respectively.There was no statistically difference between two cortical mapping techniques,chi-square test of paired comparison of enumeration data,P<0.01.Conclusion BOLD fMRI was a high sensitive and reliable technique to locate the position of the primary motor areas and their spatial relation with adjacent tumor,especially for the presurgical planning in patients with central area brain tumor.