运动诱发电位对脑动脉瘤蛛网膜下腔出血后迟发性脑血管痉挛的诊断性意义分析

Value of motor evoked potential in diagnosis of late-onset cerebral vasospasm after aneurysmal subarachnoid hemorrhage

摘要:

目的 研究运动诱发电位（motor evoked potential，MEP）对脑动脉瘤蛛网膜下腔出血（aneurysmal subarachnoid hemorrhage，aSAH）后迟发性脑血管痉挛（vasospasm，VS）的诊断意义。方法 选取2015年5月~2017年5月在陕西省第四人民医院和第四军医大学西京医院神经外科重症监护病房（Intensive Care Unite，ICU）住院治疗的高分级（Hunt-Hess分级Ⅲ-Ⅴ级）的伴有或不伴有迟发性VS的aSAH患者35例，运用经颅磁刺激运动诱发电位仪来检测MEP刺激阈值的变化，运用数字减影血管造影（digital subtraction angiography，DSA）检查结果作为判定是否存在确定性aSAH后迟发型性VS的金标准。并对MEP诊断VS的敏感性、特异性、阳性和阴性预测值进行计算。结果 出现大脑皮质运动区供血动脉迟发性VS的患者，MEP的刺激阈值最小增加值为45mA，平均增加值为61.55mA；在未出现迟发性VS的患者，MEP的刺激阈值最大增加值为25mA，平均增加值为12.59mA；二者比较有明显差异（P<0.05）。MEP的刺激阈值增加45mA或以上对诊断迟发性VS有临床意义，其敏感性为0.85，特异性为0.86，阳性预测值为0.85，阴性预测值为0.86。结论 MEP检查能够比较准确地诊断aSAH后迟发性VS，其可以作为一种床旁实时诊断VS的较为可靠方法。

Abstract:

Objective To investigate the value of motor evoked potential (MEP) in the diagnosis of late-onset cerebral vasospasm after aneurysmal subarachnoid hemorrhage (aSAH).Methods A total of 35 patients with high-grade aSAH (Hunt & Hess grade Ⅲ-V) with or without late-onset cerebral vasospasm who were hospitalized and treated in the Intensive Care Unit (ICU) of Department of Neurosurgery in The Fourth People’s Hospital of Shaanxi Province and Xijing Hospital of Fourth Military Medical University from May 2015 to May 2017 were enrolled. The transcranial magnetic stimulation MEP equipment was used to measure the change in MEP threshold, and the results of digital subtraction angiography (DSA) were used as the gold standard for judging the presence or absence of late-onset cerebral vasospasm after aSAH. The sensitivity, specificity, and positive and negative predictive values of MEP in the diagnosis of cerebral vasospasm were calculated.Results In the patients who developed late-onset vasospasm of the feeding arteries in the motor area of the cerebral cortex, MEP threshold was increased by at least 45 mA, with a mean value of 61.55 mA, while in the patients who did not develop late-onset vasospasm, MEP threshold was increased by 25 mA at most, with a mean value of 12.59 mA; there were significant differences between the two groups (P<0.05). An increase in MEP threshold by 45 mA or above had a clinical value in the diagnosis of late-onset vasospasm, with a sensitivity of 0.85, a specificity of 0.86, a positive predictive value of 0.85, and a negative predictive value of 0.86.Conclusions MEP helps to achieve an accurate diagnosis of late-onset vasospasm after aSAH and can be used as a reliable method for bedside diagnosis of vasospasm.