经颅多普勒对脑死亡的脑血流动力学评价

本研究采用经颅多普勒 (ｔｒａｎｓｃｒａｎｉａｌＤｏｐｐｌｅｒｕｌｔｒａｓｏｕｎｄ ,ＴＣＤ)技术观察 14例脑死亡患者的脑血流频谱图 ,测定其相关数据 ,旨在探讨脑死亡的脑血流动力学变化 ,并对ＴＣＤ诊断脑死亡做出初步评价。资料与方法一、临床资料1.脑死亡组 :1999年 7月至 2 0 0 0年 7月我院采用ＴＣＤ技术观察脑死亡患者 14例 ,其中男 10例 ,女 4例 ,年龄 2 3～ 5 1岁 ,平均 40 .6岁。脑死亡前原发疾病为颅脑损伤 6例 ,高血压脑出血 8例。2 .正常对照组 :3 0例 ,男 16例 ,女 14例 ,年龄 18～ 48岁 ,平均 3 7.4岁 ,无心脑血管性疾病…     

经颅多普勒超声监测羊脑血流方法学的建立

目的建立经颅多普勒超声(Transcranial Doppler Ultrasound, TCD)对羊脑血流速度检测及连续监测的方法.方法通过TCD超声探头在羊头不同部位寻找血流信号,并将其与羊头解剖对比研究,以及超声影像学检查协助定位等方法,确定TCD监测羊脑血流的声窗、探测深度和方向,并进行稳定性和重复性检验.结果1)颞骨颧突上、下方及眼部均可探测到血流信号,但只有颞骨颧突上方(即羊颞窗)颅骨薄而平,适于放置和固定探头;2)垂直方向探测,探测深度25～38mm时,可探测到背向探头方向的血流信号,信号较强且稳定;颅脑超声成像技术测量证实为同侧血管;3)14只羊右侧颞窗连续监测结果显示羊轻微活动后探头固定良好,监测的血流信号稳定,变异系数为2.9～4.6%;4)经立体连线定位解剖发现所测血管为Willis环后交通支发出的第一分支-大脑后动脉,超声束与血流方向的夹角在20～30°.结论所建TCD对羊脑血流速度监测方法具有良好的稳定性和重复性,且可反映右脑血供.     

经颅多普勒超声对颈椎病患者脑底动脉的评价

颈椎病又称颈椎综合征，是一种骨骼的退行性病理改变，发病率随年龄的增长而增多，50岁左右的人群中有25%的人患过或正在患此病。本文对100例临床诊断颈椎病，X线：颈椎骨质增生(椎体有不同程度唇样变及锥间隙变窄)患者的经颅多普勒(TCD)检测结果进行总结分析，以探讨TCD对颈椎病患者脑底动脉检测的临床价值。     

经颅多普勒超声对颅脑损伤患者的脑血流分析

颅脑损伤的发生率占全身损伤的10％～15％，由于外力的大小和作用于头部的方式及部位不同，脑损伤发生的程度及分布也不相同。我院自1994年以来应用经颅多普勒（TCD）超声对96例颅脑损伤患者伤后脑血流变化情况进行了观察，现报告如下。     

经颅多普勒超声在高血压病中的应用

本文报告我院用经颅多普勒超声(TCD)对90例高血压病人的脑血管进行检测分析,根据血流速度及频谱图象的改变分为三种类型:血流加速脑血管痉挛型、血流缓慢脑供血不足型及脑动脉硬化型,TCD检测异常率达96.67%,脑血管痉挛、脑供血不足组流速测值分别与正常组对照,P<0.01,均有非常显著性差异。     

尼莫地平治疗血管性头痛的经颅多普勒研究

目的:研究尼莫地平治疗血管性头痛的经颅多普勒改变及临床意义。方法:应用经颅多普勒超声技术(TCD)检测120例血管性头痛患者服药前及服药后50分钟、100分钟的脑血流改变。结果:①120例血管性头痛患者服药前105例TCD检测异常,收缩期峰值流速(Vs)增高98例,占异常中的93％,服药后100分钟Vs有明显下降,与服药前比较有显著差异(P<0.01);③120例血管性头痛患者服药前74例TCD检测脉动指数(PI)降低,服药后100分钟有明显增高,与服药前比较有较显著差异(P<0.05)。结论:尼莫地平能明显改善血管性头痛的脑血流异常指标,可作为治疗血管性头痛的首选药物之一。     

经颅多普勒超声对小儿血管性头痛评价

目的：了解小儿头痛颅内动脉的血液变化并提供有参考价值的数据。方法：采用经颅多普勒（TCD）诊断仪对40例临床以头痛为主的患儿进行检测。用2MHz探头经颞窗监测双侧大脑中动脉，大脑前动脉及大脑后动脉收缩期血流速度及脉动指数。结果：头痛患儿脑动脉收缩期血流明显高于正常对照组（P＜0．01）。结论：TCD对不儿原因不明的头痛判断有无脑血流异常，进行此项检测有着重要临床意义。可作为早期诊断筛选作用。     

偏头痛的经颅多普勒超声研究概况

偏头痛是神经系统常见疾病之一,其发病机理不详。１９３８年Ｇｒａｈａｍ等［１］提出偏头痛的血管学说,认为偏头痛是由于脑血管痉挛继发脑血管扩张引起的。虽然以后提出神经学说、体液学说及免疫学说等,但是最终均导致脑血管的异常舒缩反应引起头痛发作。有关偏头痛的...     

经颅多普勒超声监测脑血流在麻醉手术中的应用

目前有多种有创或无创的方法可以在麻醉手术中监测患者脑血流和脑代谢,不同的方法具有各自的使用范围.经颅多普勒超声因其便捷、连续、可重复性强等特点,可用于监测术中脑血流自动调节功能失调的高危患者和术中采用特殊体位的患者,而使用经颅多普勒超声监测到的脑血流变化可能与患者术后中枢神经并发症相关.该文就经颅多普勒超声监测脑血流在...     

功能性经颅多普勒超声的研究进展

经颅多普勒超声(TCD)是一种具有实时性的无创的诊断工具，它可连续同时监测双侧的脑血流速度(CBFV)，TCD结合彩色多普勒能量图或磁共振血管成像技术可无创地测量大脑血流量。功能性经颅多普勒超声(functional transcranial Doppler ultrasonography，fTCD)是研究认知活动时双侧半球不同动脉血流速度变化的技术。本文对有关fTCD的研究做一综述。     

Transcranial Doppler monitoring compared with invasive monitoring of intracranial pressure during acute intracranial hypertension

Objective. To determine whether a simple transcranial Doppler waveform variable–pulsatility difference (systolic - diastolic blood flow velocity) can serve as a measure of critical changes in cerebral perfusion. Methods. Thirteen pigs were anesthetized (anesthesia maintained with halothane) and ventilated to maintain normoxia and normocarbia. To measure mean arterial pressure, hemoglobin, and blood gases, the right carotid artery was cannulated. The right intracranial lateral ventricle was cannulated to measure and increase intracranial pressure; the right internal jugular vein was cannulated in 8 of 13 pigs to measure jugular venous oxygen saturation and to calculate cerebral arteriovenous oxygen content difference. Intracranial pressure was also monitored continuously with a subdural bolt in the contralateral frontal region, and blood flow velocity in the middle cerebral artery was measured with a transcranial Doppler probe on the right orbital region. Intracranial pressure was increased in increments of 10 to 20 mmHg by infusing saline through the ventriculostomy catheter until the transcranial Doppler indicated that blood flow velocity had ceased, at which point all variables were allowed to return to baseline. If mean arterial pressure failed to return to baseline, epinephrine, 0.01 to 0.1 µg/kg/min, was infused. Useful data were obtained from 8 pigs and were analyzed separately for pigs that received epinephrine (n = 4) and those that did not (n = 4). Results. Transcranial Doppler measurements correlated more closely with cerebral perfusion pressure = (mean arterial pressure – intracranial pressure) than with intracranial pressure. In the range of 30 to 60 mmHg, cerebral perfusion pressure correlated linearly with the pulsatility difference. The closest nonlinear correlation (third order polynomial relationship) was noted between cerebral perfusion pressure and pulsatility difference (r = 0.8, P < 0.001, n = 217), for the animals that did not receive epinephrine. When a cerebral perfusion pressure <60 mmHg and a cerebral arteriovenous oxygen content difference >6.5 vol% were used to define limits of abnormal, pulsatility difference was a sensitive and specific indicator of abnormality in either variable. Pulsatility difference of >70 cm/sec had >77.1% and 86.7% positive accuracy rate, and <0% and 14.3% negative accuracy rate for abnormal cerebral perfusion pressure (CPP) and cerebral arterio-venous O₂ (C[a-v]O₂), respectively. Conclusions. In pigs with induced diffuse intracranial hypertension, noninvasive transcranial Doppler waveform monitoring of pulsatility difference can identify increased cerebral oxygen extraction and dangerously decreased cerebral perfusion pressure.     

经颅多普勒诊断颅内动脉瘤术后脑血管痉挛

目的探讨经颅多普勒检查在颅内动脉瘤术后脑血管痉挛诊断中的价值。方法采用临床病例分析统计方法,归纳、分析颅内动脉瘤术后患者的经颅多普勒检查资料。结果33例患者中,有15例在术后出现不同程度的脑血管痉挛症状,比较有、无症状患者MCA和eICA流速变化,发现有症状性血管痉挛的患者,MCA血流速度增加值明显大于无症状组。结论经颅多普勒可以在患者出现临床症状以前,早期发现颅内动脉的血流速度增高,指导临床医生及时调整治疗方案,避免造成严重并发症。     

Acute increase in intracranial pressure revealed by transcranial Doppler sonography

Increased pulsatility of blood flow in the basal cerebral arteries recorded with the use of transcranial Doppler sonography (TCD) corresponds to increased intracranial pressure (ICP) to near the level of the diastolic arterial blood pressure. We describe the case of a 39-year-old woman who developed acute reduction in consciousness, anisocoria, gaze deviation, and right-sided hemiparesis 2 days after resection of a relapsed astrocytoma. MRI revealed only a moderate enlargement of the ventricles, but TCD revealed highly pulsatile waveforms of all basal cerebral arteries, showing a biphasic pattern with diastolic backflow. This pattern was interpreted as a massive increase in ICP with imminent danger of cerebral circulatory arrest corresponding to acute malresorptive hydrocephalus. External cerebrospinal fluid drainage was immediately undertaken, revealing excessive ICP of more than 50 cm H(2)O. Twenty-four hours after this intervention, both the ICP and the Doppler waveforms had returned to normal. This case illustrates the usefulness of TCD for diagnosing a critical but potentially reversible acute increase in ICP with imminent cerebral circulatory arrest.     

Transcranial Doppler waveform changes due to increased cerebrovascular resistance and raised intracranial pressure in a patient with cirrhosis: A difference in shapes,not in numbers

We report and discuss a case that illustrate the clinical utility of transcranial Doppler (TCD) ultrasound in a patient with cirrhosis. A 43-year-old female presented with acute decompensation of cirrhosis with hepatic encephalopathy, requiring mechanical ventilation. TCD showed low diastolic flow velocities and high pulsatility index (PI) consistent with increased cerebrovascular resistance (CVR). The flow velocities and PI normalized over a period of few days and correlated well with neurological improvement after treatment. Subsequently, the patient developed a large intracerebral hemorrhage with mass effect. The TCD measurements in intracranial hypertension were similar to those with cirrhosis and hepatic encephalopathy. However, the windkessel notch in the systolic phase of TCD waveform, related to the distensibility of arterial wall, was absent during raised intracranial pressure (ICP). The absence of a windkessel notch may help to differentiate a high downstream resistance due to raised ICP from increased CVR.     

TCD对颅内静脉血流的检测

对40例正常人和50例缺血性脑血管病(ICVD)患者行颅内静脉血流检测。经颞窗探测大脑中深静脉(DMCV)和基底静脉(BV)。结果示,探测深度DMCV为44~70mm,BV为48~88mm,血流方向背离探头,平均血流速度(Vmean)9~20cm/s,搏动指数0.16~0.50。正常人和患者Vmean无显著差异,但ICVD患者的探测成功率低。     

Transcranial Doppler Monitoring of a Migraine with Aura Attack From the Prodromal Phase to the End

SYNOPSIS
Transcranial Doppler sonography (TCD) was performed in a case of migraine with aura during the different phases of the attack. In the prodromic period our patient showed a slight central deficit of the seventh right cranial nerve and hypesthesia in her right arm. TCD indicated a remarkable decrease of the mean flow velocity (MFV) of the left middle cerebral artery (MCA). During the headache phase and when the signs and symptoms subsided, TCD showed an increase in MFV of both middle cerebral arteries with normal symmetry. An electroencephalogram (EEG) demonstrated a left temporal disorder. A month later a cranial CT scan, an EEG, and TCD were normal. In our opinion all these findings suggest a focal reduction in cerebral blood flow in the prodromic phase.     

Transcranial Doppler Sonography in Chronic Paroxysmal Hemicrania

SYNOPSIS
Three patients with chronic paroxysmal hemicrania (CPH) (1 M, 2 F) and 9 healthy controls (8 M I F) were studied with transcranial Doppler (TCD) sonography. One patient who was studied during the spontaneous attacks hyperventilated markedly. Middle cerebral artery velocity (V_MCA) was measured in the first attack, and anterior cerebral artery velocity (V_ACA) in the second attack, respectively. V_MCA and V_ACA decreased bi-laterally during attack. V_MCA started to decrease at an early stage of the attack, i.e. prior to the major hyperventilation that was observed during the attack. V_ACA on the symptomatic side decreased less than that on the other side (P<0.05). Cerebral vasomotor reactivity (VMR) was expressed as the percentage change in mean blood flow velocity as a function of end-tidal PCO₂ (P_ETCO₂) reduction induced by voluntary hyperventilation (DV/DP_ETCO₂). In the 3 patients, a slightly lowered VMR was observed in the MCA and posterior cerebral artery on both sides, and in the ACA on the symptomatic side IP>0.05) in comparison with controls. These observations may imply an abnormal vascular reactivity in CPH.     

Acute intracranial hypertension and basilar artery blood flow velocity recorded by transcranial Doppler sonography: an experimental study in rabbits

Summary. The relationship between intracranial hypertension and basilar artery blood flow is not well known, and it is not yet definite that the reduction of cerebral flow depends on cerebral perfusion pressure rather than microvessel compression. The purpose of the study described here was to investigate the effect of acute intracranial pressure on the basilar flow velocity, the cerebral perfusion pressure, and the systemic arterial pressure. The basilar Doppler signal was recorded continuously in 24 New Zealand rabbits by transcranial pulsed Doppler method. The acute intracranial hypertension was induced by the progressive raising, in steps of 5 mmHg, of a saline infusion bottle connected to an epidural sensor. The intracranial hypertension induced a decrease in diastolic and mean flow velocities in the basilar artery, and an increase in the resistance index. Cerebral perfusion pressure was significantly correlated with flow parameters. The basilar diastolic flow began to decrease significantly from a 35–40 mmHg intracranial pressure and for a 37 mmHg+20 SD cerebral perfusion pressure, without significant variation of arterial pressure. Diastolic flow dropped to zero for a 53 mmHg intracranial pressure and a 30 mmHg+15 SD cerebral perfusion pressure. These results show that high intracranial pressure values are necessary for significantly reducing basilar artery blood flow. This effect, and the increase of circulatory cerebral resistance, occurred before significant changes in systemic arterial pressure.,     

经颅多普勒超声对颅内压增高的诊断价值

对２６例颅内压增高患者和３２名正常人的经颅多普勒进行，结果表明患者多普勒频谱均异常，定量指标中以Ｖｓ２／Ｖｓ１比值、ＰＩ、ＲＩ最敏感，以Ｖｄ、Ｖｍ及Ｖｓ１次之，随着颅内压增高Ｖｓ１亦减慢。文中初步讨论了颅内压增高患者的ＴＣＤ改变机理，提出了其ＴＣＤ特征，指出ＴＣＤ是诊断颅内压增高较理想的方法。     

颅内静脉血流的经颅多普勒超声研究

目的　采用经颅多普勒（ＴＣＤ） 评价颅内静脉血流。方法　应用２ ．０ ＭＨｚ 探头对８０ 例健康人颅内静脉行多普勒检测,年龄２０ ～７０ 岁（ 平均４８ ．９ 岁） 。结果　基底静脉血流信号背离探头,邻近大脑后动脉,平均流速（１３ ．６ ±２ ．２） ｃｍ ／ｓ ,并随年龄增长有减低趋势,两侧血流速度无明显差异。３４ ％ 的受试者发现大脑中深静脉,血流信号背离探头,与大脑中动脉并行,血流速度与基底静脉类似。直窦血流信号朝向探头,平均流速（１７ ．３±４ ．２） ｃｍ／ｓ 。结论　经颅多普勒可用于评价脑底静脉血流。