卒中后脑水肿——无创检测、机制及治疗探索

【作者】 王健；

【导师】 董为伟；

【作者基本信息】 重庆医科大学 ， 神经病学， 2003， 博士

【摘要】 背景及目的 脑水肿是脑部疾病患者致死的最主要原因之一。及时准确评价脑水肿的严重程度及其发展，正确处理脑水肿，关系到临床重症患者抢救成败的关键之一。 目前脑水肿的评价主要依赖CT、MRI等影像学方法，费用昂贵且不能实时测定，对临床指导有限。因此，有必要探索一种实时、无创、简便易行、可较长时期进行床旁监测脑水肿的方法，以便能及时指导脑水肿的临床判断和治疗。 生物电阻抗分析法应用于人体组成成分的检测是近年来才发展起来的一种新方法，具有快速、简捷、成本低廉、安全等特点，近年来已成为研究热点。迄今，有关脑电阻抗的无创性检测，文献尚无报道。本研究利用生物电阻抗测定原理，研制一种无创性脑水肿检测系统，测定脑卒中患者的脑电阻抗，检测结果与CT等影像学所见进行定性、定量对比，以期通过脑电阻抗的变化反映卒中后脑水肿的变化，从而建立一种可在床旁实施的，无创性、临床实时检测脑水肿的新方法。 方 法 ①通过动物实验证实阻抗测定系统的可行性，建立满足设计要求的脑水肿无创性检测系统。②测定100例正常志愿者，初步确定该检测系统所测得脑电阻抗的正常值范围。③对24例脑出血患者脑电阻抗进行了连续测定，观察脑出血后血肿侧电阻抗的变化规律；分析血肿侧电阻抗的变化与血肿及水肿体积（CT显示）的相关性。④测定47例脑梗死患者（其中16例发病时间<24h的早期脑梗死）的脑电阻抗，分析电阻抗变化与梗死病灶大小（CT及/或MRI/DWI显示）的相关性。结 果1． 无创性电阻抗检测系统的低频激励电流可透过导电性能不良的颅骨，并能较灵敏地反映颅内脑组织水含量的变化。2． 在不同测定频率下，正常两侧大脑半球电阻抗值基本对称。年龄、性别及测定时间等因素对脑电阻抗无明显影响。<WP=7>3． 脑出血患者血肿侧脑电阻抗呈现先降低后升高的特点；24h内血肿侧电阻抗变化率与血肿体积呈负相关（r=－0.8953，P<0.01），而血肿侧电阻抗变化率与血肿周围组织水肿的体积呈正相关（r=0.8811, p<0.01）。4． 脑梗死后梗死侧电阻抗均升高，高于梗死对侧。脑梗死后早期（<24h）脑电阻抗的变化与磁共振DWI显示的病灶大小呈正相关（r=0.6845, p<0.05）。结 论 1． 电阻抗是反映人脑组织电学性质的一种较稳定的物理学参数，其检测可通过无创的方式实现。2． 无创性脑电阻抗检测可较敏感地反映脑出血后血肿及血肿周围组织水肿的变化，有助于指导脑出血患者血肿及水肿变化的判断和治疗。3． 无创性脑电阻抗检测可敏感地反映脑梗死后的缺血性脑水肿，尤其是反映脑梗死后早期的细胞内水肿，有助于及时判断卒中病变的性质和严重程度。更多还原

【Abstract】 Background and ObjectivesBrain edema is the most important complication of the patients with cerebral disease, and associated with high mortality. Accurate evaluation of the edema severity and correct management on time are associated with rescuing success of the critical patient. Current methods such as CT and MRI are expensive and unconvenient, therefore, It’s necessary to explore a new method of monitoring brain edema, which can provide rapid, noninvasive, convenient monitoring edema at bedside for a long period, to contribute to clinical evaluation and treatment of brain edema.Biological electric impedance analysis applied to body component measurement, is a rapid, unexpensive and safe method developed in recently, and has become a hot spot of investigation. Up to now, there are few noninvasive studies of BEI measurement of brain. We designed a noninvasive brain edema measurement system according to BEI measure principle. The Cerebral EI(CEI) of stroke patients was measured by using this measurement system to reflect the dynamic changes of the brain edema after stroke.The results were compared with the lesion showed by CT to establish a new method of measuring brain edema which could provide noninvasive and real-time measurement at bedside.Methods①we designed a noninvasive cerebral impedance measure system, and confirmed its feasibility. ②The CEI of 100 normal volunteers, initially definited the range of normal value. ③The CEI of 24 patients with hypertensive intracerebral hemorrhage was measured continuously, which was compared with the volume of hematoma and edema showed by CT. ④The CEI of.50 patients with cerebral infarction, (19 of which onset time <24h）was measured, and the relationship between the changes of CEI and the volume of lesion showed by CT/MRI was analyzed.Results<WP=9>1． The low frequency current from noninvasive measure system could penetrate the cranium with poor electroconductivity, and could reflect the change of water content in brain tissue.2． The left and right side of CEI were almost symmetric at different frequency (P>0.05). Age,sex and measuring time did not obviously affect the CEI.3． The CEI of hematoma side was initially low and followed by high level. The rate of CEI change of hematoma side within 24h had negative correlation with the volume of hematom(r=－0.8953,P<0.01), however, the rate of CEI change of hematoma side had positive correlation with the volume of perihematomal tissue edema(r=0.8811,P<0.01).4． The CEI of infarct side were higher than contralateral. The rate of CEI change of infarct side(<24h) had positive correlation with the volume of volume ischemic lesion showed by DWI（r=0.6845, p<0.05）。Conclusions1． The CEI is a stable physical parameter for reflecting the electrical character of human brain tissue, and could be measured noninvasivly.2． Noninvasive CEI measurement could sensitively reflect the change of hematoma and perihematomal tissue edema, which contribute to clinical evaluation and treatment of cerebral hemorrhage.3． Noninvasive CEI measurement could reflect intracelluar edema early(<24 hours) after cerebral infarction, which contribute to prompt clinical judgement of the nature of lesion.更多还原