经颅多普勒与定量脑电图联合用于缺血性卒中预后的研究进展

缺血性卒中是最常见的脑血管病，具有较高的致残率及病死率。神经影像学检查在卒中的诊断、鉴别诊断和选择诊疗方案中都有重要的临床价值，但在监测卒中后脑缺血的进展及评估预后时有一定局限性。经颅多普勒与定量脑电图都具备无创、易于床旁及动态监测的特点，在临床评估脑血管病及患者脑功能状态方面具有较高的应用价值。本文就经颅多普勒与定量脑电图在缺血性卒中预后评估中的应用价值进行综述，以期为急性期缺血性卒中有效评估患者临床预后以及未来研究方向提供一些参考。     

近红外线光谱技术在神经外科应用现状

近红外线光谱仪(Near infraied Spectroscope,NIRS)利用近红外光在特定范围内可以穿透头颅的特性,无创连续床旁监测大脑局部氧饱和度(rScO_2)和间断测定大脑平均输送时间。rScO_2是脑氧代谢和脑组织氧合程度的直接指标,对缺氧相当敏感,是脑监护领域内的最新进展。本文就NIRS的基本原理、方法以及在神经外科领域目前应用现状等方面作一综述。     

定量脑电图在脑血管病临床应用中的进展

定量脑电图是近年临床中常用的无创实时脑功能监测手段。脑血管病后神经网络受损所 致的神经电生理传导改变可通过皮层脑电图记录并总结出其规律性,结合计算机技术给予定量处理, 可为卒中的发展、预后以及卒中后抑郁、卒中后认知功能障碍的评估方面提供客观依据。现从定量脑 电图在卒中和卒中后相关疾病的特点及临床应用方面作一综述。     

近红外光谱成像在脑血管病诊疗中的应用价值

对脑血管病患者的脑组织氧合情况实施床旁监测,对脑血管病的诊治及预后改善有重要价值。近红外光谱成像（near infrared spectroscopy,NIRS）作为一项新兴的脑成像技术,具有价格低廉、操作便捷、非侵入性等优点,逐渐成为脑血管病研究的焦点。本文介绍了NIRS的基本原理,探讨了NIRS在急性脑梗死早期识别、梗死后再灌注疗效评估、大面积脑梗死继发恶性脑水肿预测等方面的应用价值,预测了NIRS在大脑近皮层出血病情监测中的应用前景。此外,在蛛网膜下腔出血诊疗领域,NIRS通过动态监测脑氧饱和度,在迟发性脑缺血监测及术后功能结局预测等方面也有着较大的应用潜力。最后,本文基于NIRS的优势和不足,展望了未来适合NIRS应用的临床场景。加强NIRS在脑血管病领域的研究,将使实时评估脑血管病院前、院内的精准动态成为可能。     

脑氧饱和度监测在颈动脉内膜切除术中的应用

正近红外线光谱(near-infrared spectroscopy,NIRS)监测局部脑氧饱和度(cerebral oxygen saturation,rS O2)是一种新型的局部脑氧供需平衡的监测方法。目前脑氧饱和度监测在大血管手术、心脏外科手术、神经外科手术、胸外科手术等领域都有广泛的应用,本文主要就NIRS技术监测局部脑氧饱和度的基本原理、影响因素及在颈动脉内膜切除术中的应用进行综述。一、基本原理NIRS能够穿透颅骨等组织,且在穿透时出现波长依赖型     

近红外光谱分析仪在精神疾病中的应用

作为一种脑功能成像新方法,近红外光光谱分析仪(Near-infrared spectroscopy,NIRS)越来越多地应用于脑功能性疾病发病机制的研究。目前NIRS主要应用于抑郁症、精神分裂症、惊恐障碍、进食障碍等疾病的前额叶血液动力学检测。本文分别论述其在各类疾病中的研究进展,总结NIRS现阶段应用的优点及不足,以探究NIRS作为精神障碍辅助诊断和疗效评估新手段的可能性和应用前景。     

近红外光谱技术与脑监测

利用近红外光谱技术检测脑氧饱和度和脑血流动力学是脑监测领域的最新进展。它利用近红外光穿透组织能力强的独特特性,连续无创监测脑氧饱和度,反应脑氧供需平衡状态;由动脉血氧饱和度定量变化引起的脑氧合血红蛋白和还原血红蛋白含量改变间接计算脑血流量和脑血容量。本文综述其原理及临床应用进展。     

脑微出血对缺血性卒中临床疗效影响研究进展

随着MRI技术的发展及其分辨率的提高,脑微出血的阳性检出率逐渐增加,其对缺血性卒中临床疗效的影响日益受到关注。本文基于脑微出血与缺血性卒中相关的病理生理学机制,探讨其对缺血性卒中临床诊疗和预后的影响,以为脑微出血作为缺血性卒中治疗效果和预后的影像学标志物奠定基础。     

经颅多普勒超声在脑侧支循环评估中的临床应用

脑侧支循环的建立对于缺血性卒中的预后至关重要,便捷有效的脑侧支循环评估方法对 于临床预测卒中患者预后、血管再通治疗效益与风险评价尤为重要。TCD因其可实时检测脑血流动力 学指标、无创伤、可重复、操作便捷、廉价等优点在脑侧支循环评估中发挥着不可替代的作用。本文 检索文献就TCD对脑一、二级侧支循环和脑血管反应性的检测方法、意义及临床应用进展进行综述, 以期为临床诊疗提供帮助。     

缺血性脑卒中后抑郁与临床病理因素相关性研究

目的研究缺血性脑卒中后抑郁与临床病理因素的相关性。方法回顾分析缺血性脑卒中患者临床资料,比较不同临床病理因素中缺血性脑卒中后抑郁发生率的差异,分析缺血性脑卒中后抑郁与临床病理因素的相关性。结果缺血性脑卒中后抑郁发生率为40.0%,性别、年龄、吸烟史、酗酒史、病灶部位、病灶分布和卒中部位发生率差异均无统计学意义(均P0.05),高血压史、糖尿病史、病灶体积和NIHSS评分抑郁发生率差异均具有统计学意义(均P0.05),有高血压史、有糖尿病史、病灶体积≥10cm3和NIHSS评分≥8分缺血性脑卒中患者抑郁发生率显著高于无高血压史、无糖尿病史、病灶体积10cm3和NIHSS评分8分缺血性脑卒中患者。相关性分析表明缺血性脑卒中后抑郁与高血压史、糖尿病史、病灶体积和NIHSS评分呈正相关(均rs0,P0.05)。结论缺血性脑卒中后抑郁与高血压史、糖尿病史、病灶体积和NIHSS评分密切相关,高血压、糖尿病、病灶体积≥10cm3和NIHSS评分≥8均为其危险因素。     

Checkpoints and pitfalls in the experimental neuropathology of circulatory disturbance

In neural tissue injury many pathological processes are common to different neurological disorders, including cerebral ischemia. Because ischemia has a fundamentally simple impact on neural tissue, good laboratory modeling can help improve the general understanding of the neuropathological processes involved. Summarized here are some basic principles that should be followed to ensure that cerebral ischemia studies are reproducible and informative: (i) selection of an appropriate model of cerebral ischemia in an appropriate species (although rodents are widely used for genomic studies, the use of larger animals, with brain structures macroscopically similar to those of humans, is appropriate for many studies, e.g. of white matter lesions or the pathophysiology of cerebral edema); (ii) correct maintenance of physiological parameters, including body temperature, systemic blood pressure, and blood gas tensions, under appropriate general anesthesia; (iii) selection of an appropriate method of cerebral blood flow (CBF) monitoring (decisions include whether or not the experiment requires real‐time monitoring, in vivo measurement, and CBF mapping); (iv) appropriate timing of drug application in therapeutic studies (many drugs that are effective when given immediately after a short period of ischemia are ineffective in clinical trials, probably because of longer periods of ischemia and delayed drug delivery in clinical settings); and (v) multiparametric evaluation of therapeutic effect (with the recent increase in diagnosis of cases of mild stroke, measurement of mortality and infarct size have proven to be insufficient for the evaluation of therapeutic effect). Use of mild ischemia models and batteries of neurological tests for individual neurological functions, such as motor, somatosensory, and visual function, are becoming important in experimental ischemia research. In histological evaluation, assessment of the extent of both selective neuronal loss and the infarct will become mandatory. Regional analysis of each brain structure and coordination of the results with the apparent neurological dysfunction is a promising approach.     

Neurosonology in cerebral ischemia: future application of transcranial Doppler in acute stroke

Transcranial Doppler (TCD) has become a general practice in recent years in the diagnostic study of patients with cerebral ischemia. This is due to the fact that it is a rapid, noninvasive, reproducible and dynamic examination of intracranial circulation. In the acute phase of cerebral infarction, it can detect MCA occlusion with a good correlation with angiographic findings and, what is even more important, the patients who will later suffer lacunar infarctions almost always show a normal Doppler examination. Acute abnormalities can also demonstrate the mechanism of the clinical signs; the examination informs us of the existence of collaterals and severe occlusions or stenoses of the extracranial arteries, and can change the priority in the search for the etiological diagnosis. The diagnosis of intracranial stenoses as a cause of clinical signs is another immediate application of TCD, right from the acute phase. If in the future anticoagulation is shown to be an optimum treatment for secondary prophylaxis in intracranial stenoses, TCD will probably become the diagnostic technique of choice. The ability to predict the prognosis based on parameters obtained by TCD opens up the possibility of using it as an auxiliary technique for the selection of patients for reperfusion treatment, having in its favor that it is quick and easy to perform, and therefore suitable for treatment monitoring. It seems clear that the data obtained by Doppler in the first 6 h are a good predictor of both spontaneous improvement and early impairment, which could help to avoid treatment in patients in whom a rapid improvement can be expected. Finally, the hemodynamic data of the TCD could be of inestimable value in the assessment and monitoring of intracranial hypertension treatments and for hemodynamic management of the patient, allowing the treatment margins of the acute phase of arterial hypertension to be reliably established without compromising the perfusion pressure. In conclusion, TCD will possibly be more widely used in the future in the acute phase of cerebral infarction as a guide to diagnostic procedures, for treatment selection and for monitoring of cerebral hemodynamics.     

Clinical application of near-infrared spectroscopy (NIRS) in psychiatry: the advanced medical technology for differential diagnosis of depressive state

Near-infrared spectroscopy (NIRS) is a functional neuroimaging technique that has been increasingly employed in psychology and psychiatry. Because NIRS can detect only cerebral cortex reactivities with low spatial resolution and may suffer from contaminating signals from skin and skull, its data should be interpreted as a global index of cerebral cortex reactivities. Within these limitations, the advantages of NIRS over fMRI such as complete non-invasiveness, small measurement apparatus, high time resolution, and natural examination setting makes it the preferred method in studies of brain substrates of subjective feeling of sleepiness and fatigue, personality, conversation, and psychiatric disorders. Two-thirds of the original articles on NIRS application in psychiatry have been published by Japanese researchers. NIRS examination of psychiatric disorders using a verbal fluency task of only three minutes demonstrated their characteristics of frontal lobe function: depression was characterized by smaller activation, bipolar depression by comparable but delayed activation, and schizophrenia by reduced activation followed by re-activation during the post-task period. These characteristics can also be identified in individual NIRS data using two automatically calculated parameters. Based on these results, NIRS application in psychiatry has been approved as one of the Advanced Medical Technologies in 2009 as an aid for differential diagnosis of depressive symptoms. A lack of clinical laboratory tests for diagnosis and treatment has been one of the major difficulties for reliable diagnosis, quantitative treatment assessment, and prevention of psychiatric disorders; NIRS may be the first step toward such clinical laboratory tests in psychiatry.     

Near-infrared spectroscopy in psychiatry

Near-infrared spectroscopy (NIRS) is a functional neuroimaging technique that has been increasingly employed in psychology and psychiatry. Because NIRS can detect only cerebral cortex reactivities with low spatial resolution and may suffer from contaminating signals from the skin and skull, its data should be interpreted as a global index of cerebral cortex reactivities. Within these limitations, the advantages of NIRS over fMRI such as complete non-invasiveness, small measurement apparatus, high time resolution, and natural examination setting, makes it the preferred method in studies of brain substrates of subjective feelings of sleepiness and fatigue, personality, conversation, and psychiatric disorders. Two-thirds of the original articles on NIRS applications in psychiatry have been published by Japanese researchers. NIRS examination of psychiatric disorders using a verbal fluency task of only 3 minutes demonstrated their characteristics of frontal lobe function: depression was characterized by smaller activation, bipolar depression by comparable but delayed activation, and schizophrenia by reduced activation followed by re-activation during the post-task period. These characteristics can also be identified in individual NIRS data using 2 automatically calculated parameters. Based on these results, NIRS application in psychiatry has been approved as one of the Advanced Medical Technologies in 2009 as an aid for differential diagnosis of depressive symptoms. A lack of clinical laboratory tests for diagnosis and treatment has been one of the major difficulties for reliable diagnosis, quantitative treatment assessment, and prevention of psychiatric disorders; NIRS may be the first step toward such clinical laboratory tests in psychiatry.     

Emergency EEG and continuous EEG monitoring in acute ischemic stroke.

There is physiologic coupling of EEG morphology, frequencies, and amplitudes with cerebral blood flow. Intraoperative continuous electroencephalographic monitoring (CEEG) is an established modality that has been used for 30 years to detect cerebral ischemia during carotid surgery. These facts have generated interest in applying EEG/CEEG in the intensive care unit to monitor cerebral ischemia. However, its use in acute ischemic stroke (AIS) has been limited, and its value has been questioned in comparison with modern MRI imaging techniques and the clinical neurologic examination. This review presents evidence that EEG/CEEG adds value to early diagnosis, outcome prediction, patient selection for treatment, clinical management, and seizure detection in AIS. Research studies correlating EEG/CEEG and advanced imaging techniques in AIS are encouraged. Improvements in real-time ischemia detection systems are needed for EEG/CEEG to have wider application in AIS.     

Measurement of cerebral oxidative metabolism with near-infrared spectroscopy: a validation study.

Predicting the onset of secondary energy failure after a hypoxic-ischemic insult in newborns is critical for providing effective treatment. Measuring reductions in the cerebral metabolic rate of oxygen (CMRO(2)) may be one method for early detection, as hypoxia-ischemia is believed to impair oxidative metabolism. We have developed a near-infrared spectroscopy (NIRS) technique based on the Fick Principle for measuring CMRO(2). This technique combines cerebral blood flow (CBF) measurements obtained using the tracer indocyanine green with measurements of the cerebral deoxy-hemoglobin (Hb) concentration. In this study, NIRS measurements of CMRO(2) were compared with CMRO(2) determined from the product of CBF and the cerebral arteriovenous difference in oxygen measured from blood samples. The blood samples were collected from a peripheral artery and the sagittal sinus. Eight piglets were subjected to five cerebral metabolic states created by varying the plane of anesthesia. No significant difference was found between CMRO(2) measurements obtained with the two techniques at any anesthetic level (P>0.5). Furthermore, there was a strong correlation when concomitant CMRO(2) values from the two techniques were compared (R(2)=0.88, P<0.001). This work showed that CMRO(2) can be determined accurately by combining NIRS measurements of CBF and Hb. Since NIRS is safe and measurements can be obtained at the bedside, it is believed that this technique could assist in the early diagnosis of cerebral energy dysfunction after hypoxia-ischemia.     

Hemodynamic cerebral ischemia during carotid endarterectomy evaluated by intraoperative monitoring and post-operative diffusion-weighted imaging

OBJECTIVE: We used the result of monitoring to evaluate patients with post-operative neurological deficits attributable to hemodynamic cerebral ischemia owing to cross-clamping of the carotid artery. METHODS: We evaluated 131 carotid endarterectomy (CEA) procedures performed on 118 patients, 96 men and 22 women ranging in age from 38 to 82 years (mean: 67.1 years). For monitoring, we used a combination of somatosensory evoked potential (SEP), functional dynamic electroencephalography (EEG), near-infrared spectroscopy (NIRS) and transcranial Doppler (TCD). Patients who awoke with neurological deficits after CEA immediately underwent diffusion-weighted imaging (DWI) and magnetic resonance angiography (MRA). RESULTS: In 30 of the 131 procedures (22.9%), intraoperative monitoring disclosed abnormalities after cross-clamping of the internal carotid artery (ICA). In two of these 30 patients, shunt was not introduced, because of full recovery of monitoring after blood pressure increasing, however, one patient demonstrated transient ischemic attack (TIA). In six of remaining 28 patients who need shunt, transient hemodynamic cerebral ischemia occurred, however, all patients recovered gradually within 18 hours after CEA. No new lesions were detected on post-operative DWI of the seven patients and MRA demonstrated good patency of the carotid artery. The other 101 patients whose intraoperative monitoring after cross-clamping of the ICA did not disclose abnormalities demonstrated no hemodynamic TIA. CONCLUSION: Hemodynamic ischemia owing to cross-clamping of the ICA is rare in patients treated by CEA. However, in patients manifesting neurological deficits upon awakening from CEA, DWI and MRA should be performed immediately to facilitate their prompt treatment.     

Cerebral autoregulation in the microvasculature measured with near-infrared spectroscopy

Cerebral autoregulation (CA) is the mechanism that allows the brain to maintain a stable blood flow despite changes in blood pressure. Dynamic CA can be quantified based on continuous measurements of systemic mean arterial pressure (MAP) and global cerebral blood flow. Here, we show that dynamic CA can be quantified also from local measurements that are sensitive to the microvasculature. We used near-infrared spectroscopy (NIRS) to measure temporal changes in oxy- and deoxy-hemoglobin concentrations in the prefrontal cortex of 11 human subjects. A novel hemodynamic model translates those changes into changes of cerebral blood volume and blood flow. The interplay between them is described by transfer function analysis, specifically by a high-pass filter whose cutoff frequency describes the autoregulation efficiency. We have used pneumatic thigh cuffs to induce MAP perturbation by a fast release during rest and during hyperventilation, which is known to enhance autoregulation. Based on our model, we found that the autoregulation cutoff frequency increased during hyperventilation in comparison to normal breathing in 10 out of 11 subjects, indicating a greater autoregulation efficiency. We have shown that autoregulation can reliably be measured noninvasively in the microvasculature, opening up the possibility of localized CA monitoring with NIRS.     

多模式CT对卒中患者血脑屏障完整性和侧支循环的评估价值

多模式计算机断层扫描（computed tomography,CT）对急性缺血性卒中患者的重要性逐 渐引起临床医生的重视,在脑缺血超急性期,CT平扫可对脑出血或其他脑部疾病进行鉴别,CT血管 造影可评估血管梗死部位和侧支循环状态,CT灌注成像可以通过毛细血管的实际灌注情况来评估 脑组织的活力,并通过计算血脑屏障的表面通透性（permeability surface,PS）判断血脑屏障的完整 性,进一步指导临床医生溶栓及血管性治疗方案的制定,也可以预测卒中后患者发生出血转化的风 险。临床诊疗过程中,结合多模式CT提供的信息,可对急性缺血性卒中患者出现出血转化和临床预后 进行全面评估。