颅内占位病变患者的体感诱发磁场M80的研究

The Study of Somatosensory Evoked Fields M80 in Patients with Inracranial Space-occupying Lesion

背景与目的:脑磁图作为术前评估的一项重要内容,便于外科医生在手术前了解皮层功能状态及重要功能区的位置,从而制定合理的手术治疗计划,也可为神经内科医生提供皮层功能损伤的客观指标。本研究通过脑磁图(MEG)研究颅内占位患者的体感诱发磁场(SEF)的皮质反应波M80的潜伏期、波幅及位置,观察其变化规律。方法:选用2003年3月至2006年12月在广东三九脑科医院肿瘤神经外科住院治疗的颅内占位患者33例,其中男性15例,女性18例;年龄15～64岁。病变主要位于左侧者20例,右侧者13例。采用148信道MEG系统传感器在屏蔽室内采集患者脑磁信号。结果:全部33例健侧食指刺激者,均在对侧皮层引出了M80反应波,并得到其在相应皮层的位置;而患侧食指刺激有32例在对侧皮层引出了M80反应波,1例未引出。健侧小指刺激的30例,全部在对侧皮层引出了相应的体感M80反应波,并得到其在相应皮层的位置;而患侧小指刺激有28例记录到M80反应波,并得到其在相应皮层的位置,3例未引出。食指、小指分别刺激,两侧M80峰(患侧与健侧比较)潜伏期,统计学上无显著性差异(P﹥0.05)。但与健侧比较,患侧M80波幅(食指、小指分别刺激)明显降低,统计学上存在显著差异(P﹤0.05,P﹤0.005)。33例行MEG检查的颅内占位病变患者中,有24例神经系统查体中未发现肢体有感觉障碍。其M80峰潜伏期,患侧与健侧(食指、小指分别刺激)之间无明显差别(P﹥0.05);但患侧波幅明显降低,统计学上存在显著差异(P﹤0.05,P﹤0.005)。结论:气夹指端刺激对侧皮层体感诱发反应M80峰波波幅可作为皮层功能损伤的一个客观、早期的指标。SEF与MRI融和生成的磁源成像,不但可以准确地确定功能区和中央沟的位置,还能帮助我们更好地了解中央沟的位置和病变部位的关系。

BACKGROUND ＆ OBJECTIVE： Magnetoencephalography can facilitate the localization of cerebral eloquent areas and provide information about cortival functional impairment. In this study, we analyzed M80 of somatosensory evoked fields （SEF） in patients with intraeranial space-occupying lesion using （MEG）. Materials and METHODS：A total of 33 patients （15 males and 18 females） with intraeranial space-occupying lesion were chose in this study. MEG was performed with a 148-channels whole-head biomagnetometer （Magnes.WH2500,4-D Neuroimaging,USA） in Guangdong 999 Brain Hospital. RESULT：M80 was recorded in all patients, when the patients was stimulated on their index finger-tip. M80 was recorded from the healthy contralateral cortex in all 33 patients and from lesion cortex in 32/33 patients, whenthe patients was stimulated on the little finger-tip, M80 was recorded from the healthy contralateral cortex in all 30 patients and from lesion cortex in 28 out of 31 patients. With a stimulation on the index/little finger of the patients ,the peak latency of M80 was not statistically different in bilateral cortex（compared the lesion cortex with healthy cortex, P 〉 0.05）, but the amplitude of M80 was lower on the lesion cortex （comparing with healthy cortex, P 〈 0.05, P 〈 0.005）. Clinical examination of somatosensory was normal in 24 out of 33 cases with incracranial lesion and the peak latency of M80 was indifference （P 〉 0.05）, but the amplitude was lower （P 〈 0.05,P 〈 0.005）.CONCLUSIONS：The decreased wave amplitude of M80 maybe is a premature and objective indicator of cortical functional impairment. MEG/MSI （magnetic source imaging） can help the neurosurgeons to locate the normal brain and lesions.