经颅多普勒超声检测技术

经颅多普勒超声检测技术 发表者:何建明 (访问人次:2558) 经颅多普勒超声检测技术何建明 (一) 多普勒超声检测血流速度的基本原理 经颅多谱勒是利用超声多普勒效应来检测颅内脑底主要动脉的血流动力学及血流生理参数的一项无创性检查方法。1982 年挪威学者Aaslid 在世界上率先报道了经颅多谱勒超声技术，他将低发射频率(2 M Hz) 与脉冲多普勒技术相合， 使超声声束得以穿过颅骨较薄的部位(特定的声窗)，直接获得在距离及规定取样容积内的脑底血管多普勒频移信号。近年来，经颅多谱勒采用经微机进行多普勒频谱快速富里叶(Fourier)转换分析，显示并计算了如收缩期峰速度、舒张期末速度、平均速度、收缩峰与舒张期末血流速度比值(S,D)、搏动指数(PI)、阻力指数(RI) 等一系列的生理参数指标，能帮助临床对各种脑 血管病进行正确的分析。 1842 年，奥地利学者克约斯琴?约翰?多普勒描述了一种物理学效应。他在观察来自星球的光色变化时，发现当星球与地球相向运动时，光色向光谱的紫色端移位，表明光波的频率升高;而当星球与地球背向运动时，光色向光谱的红色端移位，表明光波的频率降低。这种物理学现象被命名为多普勒效应。多普勒超声诊断仪是利用多普勒效应对血流进行探测的仪器。探头作为超声波的发射器和接收器，这样的结构检测出来的频率变化，则是由于反射物(血细胞) 位移所引起的。在测定血流速度时，超声波在组织中的传播速度和发射频率是固定不变的。这样， 所检测出的血流速度V 和真实的血流速度,V,之间存在一个非 常简单的关系:V ,,V,cosθ 式中的θ是超声束与血流方向之间的夹角。从式中不难看出，超声束与血流方向之间的夹角越小，其结果越接近真实血流速度。在进行脑血管检测时，我们无法估计超声束与血管走向之间的夹角。但由于脑底血管与超声窗口的解剖位置相对恒定，这样就有了一个便于测量真实血流速度的解剖学基础，即超声窗口对超声束入射部位的限制决定了只能以小角度检测颅内血管的血流速度。因此，可以略去这一角度形成的误差，即认为超声束与血管走向之 间的夹角为零。 (二) 检测方法 1(颅外段血管检测 颅外段血管检测包括颈总动脉、颈外动脉、颈内动脉颅外段。行颅外段动脉全面检对正确识别颅内血流动力学改变有重要意义。在颈总动脉分叉处和颈内动脉最易发生狭窄或闭塞，如果病变进程较为缓慢则可在颅内建立侧枝循环，充分了解这一点才可以避免将侧枝循 环效应判断为颅内血管狭窄的错误。 病人去枕仰卧位，头偏向对侧，将4 M Hz 探头置于胸锁乳突肌外侧，从近端到远端移动探头对颈总动脉进行完整的观察，检测时应注意使超声与血管走行方向保持在45?角的 位置。角度过大或过小都会影响计算出来的血流速度。 一般在甲状软骨水平分出颈外动脉，向前上方对其进行追踪检测和。从颈总动脉分叉处向后上方外侧追踪观察颈内动脉直至不能检测为止。正常情况下， 对颈总动脉，颈外 动脉的检测不存在识别上的困难。颈总动脉，颈外动脉和颈内动脉的频谱形态有明显区别， 前两者都具有很强的搏动性。 2(颅内段血管检测 确定声窗是经颅多谱勒检测成功的第一步。声窗即是超声波能够穿透颅骨而没有严重衰减的通道。目前已经确定并能应用于临床的主要有三个“窗”， 即颞窗、眶窗和枕窗。一个良好的颅内血管多普勒信号的获得，在确定了声窗之后，更有赖于操作者熟练的技术，使 探头在最佳的位置和角度，才能得到足够的多普勒超声信号。 (1) 颞窗:颞窗是在颧弓上方、眼眶外缘和耳之间的范围内。此区内又可分为前、中、后窗。由于超声穿透颞窗取决该部位颅骨的厚度，因而在不同年龄、性别的人之间有着不同程度的差异。在青壮年通常有较大的范围可以获得理想信号，在老年由于骨质增厚，颞窗往 往缩小甚至缺如，这在老年女性受检者中表现尤甚。 在颞窗检测时，受检者取仰卧位，头置正位， 在检测局部涂以足够的导声耦合剂，以适度的压力保持探头和皮肤良好接触，又不至把耦合剂挤压出去并引起病人的不适感。采用频率为2 M Hz 的聚焦发射探头，深度一般先定在55 ,60cm 之间，在此深度最易获得多普勒信号。当发现多普勒信号后， 再轻微移动或倾斜探头， 选择最佳探头位置，以得到最强、最清晰的多普勒频移信号。经颞窗可以检测大脑前动脉、前交通动脉、大脑中动脉、颈内动 脉终末段、后交通动脉、大脑后动脉和基底动脉分叉处。 (2) 眶窗:受检者仰卧，头置正位，双目闭合， 使用2 M Hz 探头，放在眼睑上，不需用力压，只要保持探头与皮肤接触即可。多普勒能量降到5 , 并尽可能缩短在眼部的检 测时间。经眶窗检测的重点为颈内动脉虹吸段和眼动脉。 (3) 枕窗:受检者低头屈颈，使头颅和环椎之间的空隙开大。探头放在颈后正中线枕骨粗隆下1(5 ,2cm 处，声束指向眉弓， 使其经枕骨大孔入颅。此窗口可以检测到椎动 脉颅内段、小脑后下动脉和基底动脉。 (三) 正常脑血管多普勒频谱及各血流参数 典型的正常经颅多普勒频谱图形是由一系列连续而有规律、与心动周期一致的脉搏波动图组成。其形成近似于一个直角三角形，每个频率占据一个心动周期。频率外层曲线由上升支和下降支组成，上升支与零基线的夹角称α角，收缩期出现两峰， 即S1 峰、S2 峰，舒张早期形成第三峰， 即D 峰。从收缩期开始到最高血流速度的时间称峰时(图44)。 在频谱上某一瞬间从零基线到最高血流速度之间的速度分布范围称为频宽。高能量信号集中在周边，色彩较深， 低能量信号分布在频谱的下边， 色彩较淡。由此形成窗口，称“频窗”。频窗的形成主要是由于血流在血管内的“层流” 所引起， 血液层流状态被改变，频窗也消失。值得注意的是有时会出现频窗消失的假象，如声束与血管的角度不恰当，超声反射能量过强等。因此在检测时，要力求找到最佳透射角，选择合适的超声发射功率。 图44 正常经颅多普勒频谱示意图 颈内动脉与颈外动脉频谱形态有显著区别，颈内动脉血流与颅内动脉的血流特征相同，阻力相对较低，下降支比较平缓，颈外动脉为高阻力型，有外周血管的特征，收缩峰高尖， 下降支陡峭，舒张期切迹明显。 of outside end; next wipe to sampling of parts, as Board head or top Department pipeline, then from tube head Shang carefully to will swab child into--will its all heap into until tube Central. Sterilization bags: bags must be purchased and sterilization of used only tear heads, providing local opened her bag, place the sample in, then roll up at the top of the bag, solid cord in prison; the bottom should be folded twice, so that the cord will not penetrate the plastic bags allow sample disclosure. When the sample collection, sample collection as well as conditions such as the temperature of the product, when, together with spike marks, samples, records together into the Inspector's notes, sample sample additional samples can be collected from sample number, date, number, and other identifying information for the first person to differentiate. When sterile samples collected, and one of the most important rule is: never contaminated the sample. Need samples to collect all the additional samples collected very carefully to ensure that no violations of this rule. Second, the microbiological characteristics of the sampling programme is a small sample of test results illustrate a large number of food hygiene, so that the representativeness of the sample for analysis is essential, that is, sample number, size and nature of major impact on the results. To ensure the representativeness of the sample, first a scientific sampling programme, then use appropriate sampling techniques and sample preservation and transport keep samples in their original condition. Whatever the methodfor urgent air dryer drying (on the kamaboko). (3) measuring glassware should be naturally drain cannot be baked in the oven. Glassware storage to provide storage, four in test case, to secure, high, great instruments in it. Required for long-term preservation of grinding pad between the instruments in a piece of paper, so as to avoid a long stick. Section II national standard specifications of the experimental laboratory water GB/T6682-1992 water for analytical laboratory specifications and test methods of chemical analysis of water and inorganic trace analysis, experiments are divided into 3 levels: level water, secondary, tertiary water. Analysis laboratory water should meet Xia table by column specifications: project a level two level three level pH value range (25 ?)--5.0-7.5 conductivity rate (25 ?), mS/m ? 0.01 ? 0.10 ? 0.50 can oxidation material *to (O) meter+,mg/L-? 0.08 ? 0.4 sucking photometric (254nm,1cm light drive) ? 0.001 ? 0.01-evaporation residue (105 ? ? 2 ?), mg/L-? 1.0 ? 2.0 soluble Silicon *to (SiO2) ? 0.01 ? 0.02 meter+,mg/L-section III solution the general concepts and preparation of a solution, solution definition and characteristics are two substance formed by the mixture of two or more (mixture). These substances are even at the molecular level, that spread reached the molecular level. Solution is part of the chemical composition and physical properties of the same mixture of a homogeneous system. Classification divides according to the aggregation solution, solution gas, liquid solution (often called liquid solution) and solid solution (also known as solid solution solid solution). Solution the term traditionally refers to the liquid solution. Formed by means of a liquid solution: gases dissolved in liquids, solids dissolved in liquid and 经颅多普勒频谱参数包括血流速度、搏动指数、收缩峰与舒张期末血流速度比值、阻力指数。血流速度测定是经颅多普勒频谱分析的主要参数，其中包括收缩峰血流速度(V S)，平均血流速度(V m )，舒张期末血流速度(Vd)。搏动指数(PI)，收缩峰与舒张期末血流速度比值(S,D)， 这两个参数是反映血管顺应性和血管弹性的指标， 阻力指数(RI) 是反应脑血管的舒缩状态即阻力状况的指标。计算如下: PI ,收缩峰血流速度,舒张期末血流速度,平均血流速度 S,D ,收缩峰血流速度,舒张期末血流速度 RI ,收缩峰血流速度,舒张期末血流速度,收缩峰血流速度 二、脑血管疾病的TCD诊断 (一) 脑动静脉畸形(Cerebral arteriovenous malformation A V M ) 脑A V M 为先天性脑血管发育异常， 其主要病理生理是畸形血管盗血， 大量脑动脉血经动———静脉短路流失，引起脑血流动力学改变。利用经颅多普勒技术，不仅可以检测畸形血管部位的异常血流，同时可以检测到所有参与供血的动脉及对侧或同侧半球存在的盗 血现象。 1(脑AV M 的TCD 表现 (1) 血流速度的改变 在正常的动静脉之间，存在毛细血管网， 可以形成正常的血管阻力。动静脉畸形时，动脉与静脉间因瘘道的存在，血管阻力下降，造成血流量的增加，血循环时间明显加快，表现出高血流速度，低阻力的多普勒血流特征，血流速度可高于正常的两至三倍之多，舒张期相对升高显著，因而收缩与舒张期流速比值(S,D ) 明显减低。供血动脉低阻力特征以搏 动指数(PI) 降低反应出来，且PI 随血流速度的增高而明显下降。 (2) 血流频谱特征 因供血动脉流速增加，收缩、舒张流速比值明显减低，致频谱出现收缩期与舒张期频移差值减少，即频谱明显增宽(图5 ,1 ,45)，越接近畸形血管团，流速越高，血流紊乱，血管扩张、迂曲，频谱越失去正常“频窗” 特征， 表现出边界毛刺样， 频窗充填，不同频率的紊乱的血流信号，层次不清，涡流，低频信号增强，高频信号减弱，或双向血流频谱。 (3) 血流音频特征 正常多普勒血流音频柔和清晰，动静脉畸形时，血流速度及流量增加，畸形血管团血流方向不同，音频信号差别较大。检测时可监听到血流声频信号洪大、粗糙、杂乱，如同机器 “隆隆样” 血管杂音， 亦可伴尖锐的乐性杂音声频。 图45 脑AV M 供血动脉血流频谱高流速、低阻力特征 (4) 颅内盗血 由于畸形血管团中阻力降低和血流速度增加使供血动脉中的压力下降，供应正常脑组织的血流被脑A V M 盗血，出现“盗血综合征”。TC D 检测可以发现异常交通动脉开放， 如大脑前动脉(A C A )、大脑后动脉(PC A ) 等血流方向逆转，血流速度增加等。 2(脑AV M 血管内栓塞疗效的TCD 评价 脑A V M 的主要病理变化是颅内血流动力学发生改变。由于畸形盗血而出现供血动脉高流速、低阻力及交通动脉开放。当畸形血管团被栓塞，其内部阻力的增加，必然引起供血 动脉内压力上升和血流速度不同程度的降低，供应畸形病变的血流在颅内重新分配。因此，栓塞治疗后原供血动脉血流速度的改变是评价疗效的重要指标。我们通过对170 例脑A V M 的TC D 观察，发现栓塞完全的供血动脉其舒张期末流速(Vd) 降低率大于收缩期峰值流速(Vd) 降低率，说明Vd 的变化更能敏感地反映供血动脉远端阻力的改变;单支供血的A V M 栓塞疗效远比多支供血的A V M 效果满意，多支供血的A V M 情况较复杂，表现为被栓塞的供血动脉其平均流速及PI 值恢复或接近正常， 未栓塞的供血动脉血流速度增减不等， 增高愈显著的供血动脉其PI 值降低愈明显。表明栓塞的供血动脉停止对畸形的 供血， 未栓塞的供血动脉对畸形的供血增加，认为与栓塞后颅内血流再分配有关。 3(诊断与鉴别诊断 脑A V M 的TC D 诊断:?供血动脉表现高流速，低阻力，PI 降低或明显降低，收缩,舒张比值下降;?血流频谱表现为收缩期频移与舒张期频移差值减少， 即频谱明显增宽，舒张期弥散，收缩峰不清晰，或频谱紊乱，不，边界毛糙不整;?血流声频洪大，粗糙， 如机器“隆隆样” 血管杂音或尖锐的乐性杂音声频;?颅内盗血征象。 根据脑A V M 血流动力学变化特点， 结合临床病史， 有助于鉴别脑血管痉挛与血管 狭窄。 脑血管痉挛与蛛网膜下腔出血密切相关，多普勒血流速度为均匀性升高，收缩峰锐利， 收缩与舒张期流速对称性升高，PI 在正常范围。 动脉狭窄多见于各种原因的动脉粥样硬化， 非特异性颅内动脉炎， 动脉血栓形成等。多普勒血流速度升高的特点为节段性流速增加， 且狭窄远端的流速可减低或正常，频谱湍 流，频窗充填，能量较弱，收缩期频谱表现为“窄带型”。 根据脑A V M 血流特征性改变，TC D 可以做出明断， 但对于动脉远端小型(直,2cm ) 畸形者供血动脉血流速度和搏动指数无明显改变，TC D 诊断较为困难。因此，TC D 检查无明显异常改变者也不能排除脑A V M 的存在，必要时需进行脑血管造影确诊。 4(临床评价 脑A V M 的诊断一般要依靠脑血管造影和CT 扫描，但均不能获得颅内血流动力学信息，TC D 能实时、动态观察畸形供血动脉高流低阻的血流特征，了解引流静脉及颅内盗血情况，提供血流动力学参数，同时根据血流动力学参数的变化，对血管内栓塞治疗效果进行客观地评估。因而，TC D 可作为是脑A V M 诊断、疗效评估及随访的一种无创性检查手段。 (二) 颈动脉海绵窦瘘(Carotid cavernous fistulas CCF) 颈动脉海绵窦瘘是由于颈内动脉海绵窦段及其分支损伤后与海绵窦之间形成异常通道所致。患者可出现患侧搏动性眼球突出，触诊可看到眼球有震颤，听诊可闻及连续性杂音，并出现眼球运动障碍和视力减退等。TC D 检测的意义在于明确患者血流动力学改变，颅内侧枝循环代偿情况及引流静脉途径，也可作为评价血管内治疗效果及随访的无创性检查手 段。 1(颈动脉海绵窦瘘的TCD 表现 (1) 患侧颈内动脉瘘口近端高流速，低阻力 图46 TCD 显示颈动脉海绵窦瘘ICA 血流频谱 A 栓塞前TCD 示瘘口以下ICA 频谱 B 栓塞后TCD 示ICA 血流频谱 of outside end; next wipe to sampling of parts, as Board head or top Department pipeline, then from tube head Shang carefully to will swab child into--will its all heap into until tube Central. Sterilization bags: bags must be purchased and sterilization of used only tear heads, providing local opened her bag, place the sample in, then roll up at the top of the bag, solid cord in prison; the bottom should be folded twice, so that the cord will not penetrate the plastic bags allow sample disclosure. When the sample collection, sample collection as well as conditions such as the temperature of the product, when, together with spike marks, samples, records together into the Inspector's notes, sample sample additional samples can be collected from sample number, date, number, and other identifying information for the first person to differentiate. When sterile samples collected, and one of the most important rule is: never contaminated the sample. Need samples to collect all the additional samples collected very carefully to ensure that no violations of this rule. Second, the microbiological characteristics of the sampling programme is a small sample of test results illustrate a large number of food hygiene, so that the representativeness of the sample for analysis is essential, that is, sample number, size and nature of major impact on the results. To ensure the representativeness of the sample, first a scientific sampling programme, then use appropriate sampling techniques and sample preservation and transport keep samples in their original condition. Whatever the methodfor urgent air dryer drying (on the kamaboko). (3) measuring glassware should be naturally drain cannot be baked in the oven. Glassware storage to provide storage, four in test case, to secure, high, great instruments in it. Required for long-term preservation of grinding pad between the instruments in a piece of paper, so as to avoid a long stick. Section II national standard specifications of the experimental laboratory water GB/T6682-1992 water for analytical laboratory specifications and test methods of chemical analysis of water and inorganic trace analysis, experiments are divided into 3 levels: level water, secondary, tertiary water. Analysis laboratory water should meet Xia table by column specifications: project a level two level three level pH value range (25 ?)--5.0-7.5 conductivity rate (25 ?), mS/m ? 0.01 ? 0.10 ? 0.50 can oxidation material *to (O) meter+,mg/L-? 0.08 ? 0.4 sucking photometric (254nm,1cm light drive) ? 0.001 ? 0.01-evaporation residue (105 ? ? 2 ?), mg/L-? 1.0 ? 2.0 soluble Silicon *to (SiO2) ? 0.01 ? 0.02 meter+,mg/L-section III solution the general concepts and preparation of a solution, solution definition and characteristics are two substance formed by the mixture of two or more (mixture). These substances are even at the molecular level, that spread reached the molecular level. Solution is part of the chemical composition and physical properties of the same mixture of a homogeneous system. Classification divides according to the aggregation solution, solution gas, liquid solution (often called liquid solution) and solid solution (also known as solid solution solid solution). Solution the term traditionally refers to the liquid solution. Formed by means of a liquid solution: gases dissolved in liquids, solids dissolved in liquid and 经眶窗检测， 患侧颈内动脉流速明显增高，PI 值降低， 若瘘口位置较低，在眶窗有时只能探出流速较低或正常的血流信号，而在颞窗将探头稍斜向后下常常可探及一异常高流低阻的血流信号，为瘘口处或瘘口以下的颈内动脉。用4 M Hz 探头在颈部检测，可发现颈 内动脉流速明显增高，PI 值降低(图46)。 (2) 瘘口远端血流速度降低 患侧大脑中动脉、大脑前动脉血流速度低于健侧，患侧大脑后动脉、健侧大脑前动脉流 速正常或代偿性增高。 (3) 眼上静脉异常 图47 颈动脉海绵窦瘘经眼上静脉引流 A 栓塞前TCD 所示眼上静脉血流频谱 B 栓塞后异常眼上静脉频谱消失，TCD 示正常眼动脉频谱 C 彩色多普勒血流显像示异常眼上静脉 D 栓塞后正常眼动脉 E DSA 示海 绵窦及增粗的眼上静脉 F 栓塞后DSA 结果 由于患侧颈内动脉血流分流到海绵窦内，窦内压力过高，血流流入与海绵窦相通的各静脉中，受动脉血流的影响，眼上静脉代偿性扩张，管壁增厚，呈动脉化改变。多普勒表现为眼上静脉流速增高，血流反向， 搏动性增强(图5 ,1 ,47)。当颈动脉海绵窦瘘较严重，海绵窦内压力过高时，动脉血可经海绵前、后间窦流向对侧海绵窦。TC D 检出双侧动脉化、 血流反向的眼上静脉频谱。 (4) 频谱形态及声频异常 患侧颈内动脉虹吸段频谱紊乱，波峰融合，边缘不清，同侧大脑中动脉，大脑前动脉频 谱正常，有时可出现紊乱的频谱波形，声频粗糙似机器隆隆样回声。 (5) 盗血现象 瘘口较大，流速过高可产生虹吸作用，出现明显的盗血现象，表现为对侧颈内动脉血流通过对侧大脑前动脉，同侧大脑前动脉A1 段流向瘘口，同侧大脑后动脉通过后交通动脉向瘘口倒灌，此时双侧大脑前动脉，患侧大脑后动脉血流速度增高，患侧大脑前及颈内动脉终末端血流方向逆转，恰与正常情况下的双向血流调转方向，因而很容易将二者混淆。压迫颈总动脉可鉴别:正常时压迫颈总动脉，大脑前动脉血流方向倒转，颈内动脉终末端流速明显 降低或消失，颈动脉海绵窦瘘时压迫颈总动脉可见双向血流均增高。 (6) 侧枝循环检测方法 颈动脉海绵窦瘘血管内栓塞治疗的目的在于阻塞瘘口，尽可能保持颈内动脉通畅。当瘘口太小或栓塞困难时，需行患侧颈内动脉闭塞。因而了解患者Willis 环代偿能力极为重要。TC D 能实时、准确地检测前、后交通动脉代偿情况，为必要时行一侧颈内动脉闭塞提供参考依据。检查方法: 经颞窗检出瘘口侧大脑前动脉(A1) 血流信号后， 压迫同侧颈总动脉，大脑前动脉血流迅速降低并出现逆转，表明血流自对侧大脑前动脉经前交通动脉而致，前交通动脉代偿好。若仅有流速降低，无逆向血流或流速极低，表明前交通动脉无代偿能力或代偿欠佳。检出大脑后动脉，压迫同侧颈总动脉，大脑后动脉流速明显增高，表明后交通动脉代偿好，若大脑后动脉血流无改变或轻微增高，表明后交通动脉无代偿能力或代偿欠佳。 2(CCF 静脉引流方式的TCD 检测 在CCF 时，由于海绵窦内压力增高， 动脉化血流经其不同的途径回流， 可出现不同的静脉引流途径。TC D 经眶窗可直接观察向前或向对侧引流时双侧眼上静脉的变化，经颞窗可检测向上引流时增粗的侧裂静脉，岩上窦、岩下窦虽不能直接检测，但因其向下直接注入颈内静脉， 因而可根据颈内静脉血流变化的检测， 间接判断向后的引流途径。眼上静脉常常是主要引流静脉，由于长期高流量血逆流， 使眼上静脉代偿性扩张，管壁增厚，呈动脉化改变。TC D 能特征地显示流速增高， 低阻力及动脉化的频谱。当C CF 较严重，海绵窦内压力过高时，不但患侧症状明显，而且动脉血可经海绵窦前、后间窦流向对侧海绵窦，出现对侧的症状，临床表现双侧搏动性突眼，TC D 检出双侧动脉化、血流反向的眼上静脉。当C CF 血流以岩上窦、岩下窦引流为主时， 颈内静脉不仅流速增高，还表现为声频及频谱形态异常。由于岩上窦和岩下窦均被纤维组织形成的脑膜所包裹，可抵抗较高的血流压力，不易扩张，因而海绵窦内的动脉血以较高的压力及最短的回流途径直接流入颈内静脉，使其血流出现明显异常。TC D 表现其流速较正常增高，相差非常显著，声频异常似水泡音，频谱边界呈毛刺样改变。这是由于大量动脉血未得到缓冲而流入颈内静脉，使其压力增高， 动静脉血混流， 正常血流状态紊乱所致。在行海绵窦瘘血管内栓塞治疗后， 上述表现消失。 CCF 静脉回流途径TC D 检测结果与DSA 比较(表2)。 表2 静脉回流途径TCD 检测与DSA 比较 引流途径 TCD DSA 符合率 患侧眼上静脉 64 64 100 , 健眼上静脉 10 10 100 , 岩上窦、岩下窦 33 37 89 , 84 , 皮层静脉 21 25 3(CCF 血管内栓塞疗效的TCD 评价 TC D 检测C CF 能实时、准确观察因瘘口引起的颅内血流动力学改变及侧枝循环情况。栓塞治疗后，因瘘口闭塞，TC D 检测显示颅内血流恢复正常， 两侧血管流速对称，术前盗血及异常回流静脉血流消失，颈内动脉血流速度降低，PI 值增高， 较术前平均降低30(25 ?15(60cm,s ，PI 平均升高0(32 ?0(24 ，有时栓塞后颈内动脉流速明显低于正常， 应视为向生理状态恢复，与原本低流速不同，颅内供血较术前相比明显改变。 4(诊断 CCF 的诊断:?患侧颈内动脉瘘口近端的血流速度明显增高，PI 降低;?患侧大脑中动脉、大脑前动脉流速降低，尤以大脑前动脉明显;?颈内动脉虹吸段流速明显增高，频谱紊乱，不规则，声频嘈杂; ? 眼上静脉血流反向， 有搏动性， 且流速增高;?以下四点异常表现可提示C CF 静脉回流方式:A(异常眼上静脉搏动征， 血流反向是诊断CCF 经眼上静脉引流的可靠指标;B( 颈内静脉流速增高，声频异常， 频谱边缘毛糙是C CF 经岩上窦、岩下窦引流的征象;C( 侧裂静脉流速增高， 表明颅内静脉怒张，提示向上经皮层静脉引流;D(健侧眼上静脉或颈内静脉异常， 表明CCF 经海绵间窦向对侧引流。 of outside end; next wipe to sampling of parts, as Board head or top Department pipeline, then from tube head Shang carefully to will swab child into--will its all heap into until tube Central. Sterilization bags: bags must be purchased and sterilization of used only tear heads, providing local opened her bag, place the sample in, then roll up at the top of the bag, solid cord in prison; the bottom should be folded twice, so that the cord will not penetrate the plastic bags allow sample disclosure. When the sample collection, sample collection as well as conditions such as the temperature of the product, when, together with spike marks, samples, records together into the Inspector's notes, sample sample additional samples can be collected from sample number, date, number, and other identifying information for the first person to differentiate. When sterile samples collected, and one of the most important rule is: never contaminated the sample. Need samples to collect all the additional samples collected very carefully to ensure that no violations of this rule. Second, the microbiological characteristics of the sampling programme is a small sample of test results illustrate a large number of food hygiene, so that the representativeness of the sample for analysis is essential, that is, sample number, size and nature of major impact on the results. To ensure the representativeness of the sample, first a scientific sampling programme, then use appropriate sampling techniques and sample preservation and transport keep samples in their original condition. Whatever the methodfor urgent air dryer drying (on the kamaboko). (3) measuring glassware should be naturally drain cannot be baked in the oven. Glassware storage to provide storage, four in test case, to secure, high, great instruments in it. Required for long-term preservation of grinding pad between the instruments in a piece of paper, so as to avoid a long stick. Section II national standard specifications of the experimental laboratory water GB/T6682-1992 water for analytical laboratory specifications and test methods of chemical analysis of water and inorganic trace analysis, experiments are divided into 3 levels: level water, secondary, tertiary water. Analysis laboratory water should meet Xia table by column specifications: project a level two level three level pH value range (25 ?)--5.0-7.5 conductivity rate (25 ?), mS/m ? 0.01 ? 0.10 ? 0.50 can oxidation material *to (O) meter+,mg/L-? 0.08 ? 0.4 sucking photometric (254nm,1cm light drive) ? 0.001 ? 0.01-evaporation residue (105 ? ? 2 ?), mg/L-? 1.0 ? 2.0 soluble Silicon *to (SiO2) ? 0.01 ? 0.02 meter+,mg/L-section III solution the general concepts and preparation of a solution, solution definition and characteristics are two substance formed by the mixture of two or more (mixture). These substances are even at the molecular level, that spread reached the molecular level. Solution is part of the chemical composition and physical properties of the same mixture of a homogeneous system. Classification divides according to the aggregation solution, solution gas, liquid solution (often called liquid solution) and solid solution (also known as solid solution solid solution). Solution the term traditionally refers to the liquid solution. Formed by means of a liquid solution: gases dissolved in liquids, solids dissolved in liquid and 5(临床评价 TC D 能准确、系统地观察CCF 时颅内血流动力学的改变情况， 包括瘘口近端、瘘口处及瘘口远端血流，颅内盗血，侧枝循环代偿及静脉回流的方式。特异性地显示眼上静脉低阻力，动脉化及血流反向的异常表现， 准确提示C CF 各种不同引流方式， 压迫颈动脉后可通过交通动脉的检测判断侧枝循环代偿能力，为必要时一侧颈内动脉栓塞提供客观依据。栓塞治疗后，TC D 检测通过颅内血流的变化，回流静脉血流的消失， 颈内动脉是否通畅等指 标的观察评估疗效。 (三) 颅内动脉瘤(Intracranial aneurysm) 颅内动脉瘤是指脑动脉的局部性异常扩大，多在脑底动脉的分叉处或分支的夹角向外突出，多呈囊状。据报道约80 , 的颅内动脉瘤分布于脑低动脉环的前半部， 而颈内动脉，大脑前动脉，大脑中动脉， 前后交通动脉正处于经颅超声可探测区域内， 这是TC D 检测 颅内动脉瘤的解剖学基础。 1(颅内动脉瘤的TCD 检测 以往国内外报告认为TC D 对颅内动脉瘤检测的主要价值为瘤体破裂后蛛网膜下腔出血，导致严重并发症———血管痉挛的判断， 其敏感性高达80 , ,100 ,。我们尝试用TC D 诊断颅内动脉瘤，并与DSA 诊断结果进行比较研究， 发现TC D 检出异常频谱处与DSA 造影所示瘤体部位完全一致，所有TC D 所示瘤体内双向血流频谱，DSA 均可见清晰的 瘤体内涡流。 表3 TCD 与DSA 检测影像形态结果比较 组别 TCD DSA 瘤体内血流速度减低，收缩峰陡峭或多峰 瘤体大小1(5cm 以上，瘤体内血 不整，舒张期末流速低或断流，PI 值增高， 异常41(41,67) 流涡流;基底部多较宽;瘤体轮 多为双向血流频谱，峰值流速一般,20cm, 廓不完整，可见附壁血栓。 s ，声频似撞击样轰鸣音。 政党背景下近基线处流速极低的异常波， 瘤体大小约0(6 ,1(5cm ;涡流有 可疑4 (4,67) 边缘毛刺样，无正常波形，峰值流速一般 或不清晰;多有瘤蒂;瘤体轮廓 ,15cm,s ，声频异常。 较为完整。 瘤体大小约0(3 ,1(0cm 较小的高 正常22(22,67) 未见异常 密度影，轮廓清晰。 按TC D 检测瘤体内血流及声频不同将其分为异常、可疑及正常三组， 其相应DSA显 示见表3 。 按DSA 显示动脉瘤大小分三组，TC D 检出结果见表4 ， 巨大型与大型动脉瘤血流参 数比较见表5 (小型组TC D 检测多为正常，其流速未做统计) 表4 三组不同大小动脉瘤TCD 检测结 组别 N 检出动脉瘤样频谱 检出率 巨大型(,2(5cm) 19 19 100 , 小型(1 ,2(5cm) 30 22 73 , 小型) ,1cm) 18 4 (可疑) 22 , 表5 巨大型与大型劝脉瘤血流参数比较(,XS) 组别 n Vs (cm,s) Va (cm,s) V m (cm,s) PI 巨大型 19 38(67 (11(36) 7(78 (6(34) 17(33 (6(71) 1(76 (0(70) 大型 30 28(57 (8(60) 1(14 (2(04) 14(14 (4(02) 1(80 (0(37) P 0(32 0(015 0(262 0(813 TC D 对颅内动脉瘤的总检出率为67 ,， 动脉瘤,1c 的检出率为82 ,。巨大型和大型组动脉瘤瘤体内血流Vs 、Vd 有显著差异(P ,0(05)， 收缩峰高尖多见于巨大型， 而舒张期末断流多见于大型动脉瘤。 2(“动脉瘤样频谱” 及形成机制 从本组病例TC D 与DSA 检测结果的比较可以看出，TC D 对较大动脉瘤(,1(5cm )的检测有其特征性表现。其典型表现:瘤体内血流速度明显低于载瘤动脉血流速度，其收缩峰陡峭或多峰不整，舒张期末流速极低或断流，PI 值增高， 多为双向血流， 声频低钝，似撞击样轰鸣音(图5 ,1 ,48)。此外，我们进行了兔股动脉外伤性假性动脉瘤活体动物实验模型。在制作的72 个模型中，有69 个出现搏动性包块，均被DSA 造影证实，解剖观察发现囊腔内充满血流，囊壁内面为形态不规则的附壁血栓，彩超显像见囊腔内有快速流动的血液涡流。由此可见瘤体内附壁血栓，瘤壁不光滑，血流对瘤壁的冲击，瘤体大小、形状、部位等因素是“动脉瘤样频谱” 形成的基础。Joanna 等采用彩色多普勒超声显像技术(C D E) 观察40 例颅内动脉瘤患者， 发现动脉瘤的彩色区域和扩张性比正常动脉更大，有些动脉瘤在舒张期实际上已消失。这与TC D 所示瘤体内血流\\频谱出现舒张期断流现象是一致的。Black 等通过动物实验观察动脉瘤颈与容积之间的关系，提出动脉瘤瘤颈的直径与动脉瘤容积呈正比， 动脉瘤颈越宽， 血流冲击力越大，动脉瘤体积也越大。本组大型动脉瘤TC D 与DSA 对比结果与之相符。我们认为瘤腔内血流收缩峰速可以反应瘤体大小及血流对瘤壁的冲击力，舒张期末流速可以反应瘤体的搏动性，搏动性越大，舒张期断流越明显。异常声频是血流撞击瘤壁所致，载瘤动脉的血流速度多数无明显改变，但在巨大动脉瘤，载 瘤动脉或相邻动脉有不同程度受压时，可见相应动脉的流速增高或降低。 图48 颈内动脉虹吸段巨大动脉瘤(约3cm ?3cm) A TCD 所示瘤体内血流频谱 B DSA 结果 C 彩色多普勒血流显示结果 3(临床评价 TC D 检查颅内动脉瘤，可以了解动脉瘤部位，大小，瘤体内血流，频谱特征， 脉动指数，载瘤动脉血流速度等。TC D 对较大颅内动脉瘤(,1(5cm ) 的检测有其特征性表现，对较小颅内动脉瘤的诊断价值不肯定，直径,1cm 的动脉瘤极易被忽略，检出时表现为不典of outside end; next wipe to sampling of parts, as Board head or top Department pipeline, then from tube head Shang carefully to will swab child into--will its all heap into until tube Central. Sterilization bags: bags must be purchased and sterilization of used only tear heads, providing local opened her bag, place the sample in, then roll up at the top of the bag, solid cord in prison; the bottom should be folded twice, so that the cord will not penetrate the plastic bags allow sample disclosure. When the sample collection, sample collection as well as conditions such as the temperature of the product, when, together with spike marks, samples, records together into the Inspector's notes, sample sample additional samples can be collected from sample number, date, number, and other identifying information for the first person to differentiate. When sterile samples collected, and one of the most important rule is: never contaminated the sample. Need samples to collect all the additional samples collected very carefully to ensure that no violations of this rule. Second, the microbiological characteristics of the sampling programme is a small sample of test results illustrate a large number of food hygiene, so that the representativeness of the sample for analysis is essential, that is, sample number, size and nature of major impact on the results. To ensure the representativeness of the sample, first a scientific sampling programme, then use appropriate sampling techniques and sample preservation and transport keep samples in their original condition. Whatever the methodfor urgent air dryer drying (on the kamaboko). (3) measuring glassware should be naturally drain cannot be baked in the oven. Glassware storage to provide storage, four in test case, to secure, high, great instruments in it. Required for long-term preservation of grinding pad between the instruments in a piece of paper, so as to avoid a long stick. Section II national standard specifications of the experimental laboratory water GB/T6682-1992 water for analytical laboratory specifications and test methods of chemical analysis of water and inorganic trace analysis, experiments are divided into 3 levels: level water, secondary, tertiary water. Analysis laboratory water should meet Xia table by column specifications: project a level two level three level pH value range (25 ?)--5.0-7.5 conductivity rate (25 ?), mS/m ? 0.01 ? 0.10 ? 0.50 can oxidation material *to (O) meter+,mg/L-? 0.08 ? 0.4 sucking photometric (254nm,1cm light drive) ? 0.001 ? 0.01-evaporation residue (105 ? ? 2 ?), mg/L-? 1.0 ? 2.0 soluble Silicon *to (SiO2) ? 0.01 ? 0.02 meter+,mg/L-section III solution the general concepts and preparation of a solution, solution definition and characteristics are two substance formed by the mixture of two or more (mixture). These substances are even at the molecular level, that spread reached the molecular level. Solution is part of the chemical composition and physical properties of the same mixture of a homogeneous system. Classification divides according to the aggregation solution, solution gas, liquid solution (often called liquid solution) and solid solution (also known as solid solution solid solution). Solution the term traditionally refers to the liquid solution. Formed by means of a liquid solution: gases dissolved in liquids, solids dissolved in liquid and 型的异常频谱，常与动脉狭窄的涡流频谱有相近之处，在鉴别时应予考虑。依据以上分析，TC D 检测获得特征性动脉瘤样频谱， 对诊断颅内动脉瘤是有临床意义的，对小型的动脉瘤 可提供有价值的线索。 (四) 硬脑膜动静脉瘘(Duralarteriovenousfistula ，D A VF) 硬脑膜动静脉瘘是指动静脉直接交通在硬脑膜及其附属物大脑镰和小脑幕的一类血管性疾病，颅内没有原发血管畸形，也称为硬脑膜动静脉畸形。临床表现复杂多样，以颅内杂音，头痛，蛛网膜下腔出血等居多。本病诊断靠选择性全脑血管造影，一定要行颈外动脉造影。TC D 作为辅助检查手段，可以实时观察颅内血流动力学改变，供血动脉血流状态，颅 内盗血及引流静脉等，并提供各血管血流动力学参数。 1(硬脑膜动静脉瘘的TCD 表现 硬脑膜动静脉瘘的供血动脉较丰富，且往往是双侧对称性供血，主要供血动脉有颈外动脉的枕动脉、脑膜中动脉、咽升动脉、耳后动脉、椎动脉的脑膜后支，颈内动脉的脑幕动脉与供应脑实质的血管。因受骨性组织的限制，TC D 只能在颈部、枕后、耳后及耳廓前缘分别检测到颈外动脉起始处、枕动脉、耳后动脉、颞浅动脉。当硬脑膜动静脉瘘为海绵窦型时，在颈部检测瘘口以下颈内动脉流速增高或轻度增高，经眶窗可检测到异常的眼上静脉，血流反向，频谱动脉化，流速轻度增高，与颈动脉海绵窦瘘相似，但特征性不如其典型， 且常 常是双侧对称。病变较轻者， 颅内动脉检测常无明显异常表现。 硬脑膜动静脉瘘的TC D 表现主要为供血动脉流速高， 搏动指数降低。由于动静脉间直接交通，缺乏血管阻力， 使供血动脉表现出高流速， 低阻力特征， 这是TC D 识别供血动脉的重要依据。由于瘘口处产生湍流，使供血动脉的频谱与音频信号异常，而出现血流频谱紊乱，监听时可闻及明显的杂音。硬脑膜动静脉瘘与脑A V M 的TC D 表现均为供血动脉高流低阻特征，常常难以鉴别。主要鉴别点: ? 脑A V M 颅内动脉血流异常表现供血动脉高流低阻，颈外动脉正常，硬脑膜动静脉瘘常有颈外动脉及分支高流低阻，颈内动脉正常或异常;?脑A V M 表现患侧供血动脉异常，硬脑膜动静脉瘘往往是双侧对称性表现。 2(临床评价 TC D 可作为硬脑膜动静脉瘘的辅助检查手段，为临床提供颅内血流动力学参数，判断供血来自颈内或颈外动脉系， 对海绵窦型可作出诊断。血管内栓塞治疗后采用TC D行术前术后比较分析，评估疗效，对某些硬脑膜动静脉瘘尤其是与脑A V M 难以鉴别的需进行数 字减影脑血管造影。 (五) 烟雾病(Moyamoya disease) 烟雾病是由于先天性或获得性各种脑底动脉狭窄或闭塞引起颅底动脉异常血管网形成导致的脑血管病理改变，主要改变为颈内动脉虹吸部，终末段，大脑中动脉及大脑前动脉的起始部狭窄或闭塞，早期尤以颈内动脉终末段狭窄多见，病变多累及双侧，颅底动脉环形成大量新生的异常血管网。脑血管造影是确诊的重要手段，但它是一项有创的检查方法，通常烟雾病患者早期无典型临床表现，一般不易首选脑血管造影。TC D 可对颅底血管血流动力 学变化直接检测， 作为对烟雾病病人的筛选及随访观察手段是可行的。 1(烟雾病的TCD 表现 烟雾病的病理发展变化复杂， 临床症状多样，故TC D 也有多种表现形式。依照血管 狭窄或闭塞程度不同，可有不同的TC D 表现。 一侧颈内动脉虹吸段流速增高， 同侧M C A 、A C A 流速降低，信号较弱，对侧同名血管流速正常或增高，颈动脉压迫试验， 患侧M C A 流速降低，提示一侧IC A 狭窄。有时一侧M C A 、A C A 流速降低，频谱低脉动性，为波浪型，压迫试验， 流速无明显反应，健侧IC A 、双侧PC A 流速增高，表明血流来自健侧及后循环代偿，提示该侧IC A 闭塞。 双侧大脑中动脉，大脑前动脉血流信号消失，取而代之的是流速、方向、走形不同于正常的血流信号，双侧PC A 、椎动脉、流速异常增高， 压迫试验双侧血流速度无改变，有时可检出颈外动脉流速增高， 提示双IC A 闭塞，代偿血流来自后循环及颈外动脉。 不论是狭窄或闭塞，当有异常血管网形成时，TC D 均可检出血流方向不同，流速高低不等，频谱及声频异常，且失去正常脑底动脉解剖位置的杂乱的血流信号，且常常是双侧的异 常血流表现，这是烟雾病于检查者最直观、最典型的TC D 表现。 2(烟雾病的TCD 诊断 (1) 多发性脑血管异常血流速度增高或降低，湍流或低脉动性频谱，异常的血管走向 及血流方向。 (2) 一侧或双侧颈内动脉、大脑中动脉、大脑前动脉狭窄或闭塞M C A 或A C A 信号 消失或流速明显降低，压迫CC A ，其流速无明显改变。 (3) 侧枝循环建立，PC A 、B A 、V A 及颈外动脉流速增高。 (4) 结合临床，对不明原因的青壮年病人反复发生脑供血障碍都应怀疑本病的存在。 3(临床评价 TC D 实时客观地反应烟雾病颅底动脉血流动力学改变，尤其对早期血管狭窄的检测更优于其他影像学检查，因其无创，易于被病人接受，更适于烟雾病患者病程进展的跟踪观察。 因而TC D 检查可作为烟雾病患者早期诊断、定期随访的首选方式。 总之，TC D 作为一种无创的脑血管病检查手段，它摒弃了传统脑血流图的不准确性和脑血管造影的有创性，亦为CT 、M RI 等现代影像技术提供了脑血管血流动力学参数，成为影像诊断的重要佐证， 也是脑血管病血流动力学研究不可缺少的设备之一。然而TC D 检测尚有局限性:?少数声窗条件不良者，不能检查;?受声窗条件限制，难以评价主干远端及分支病变;?无二维声像图，带有一定的盲目性;?对操作者技术条件要求高。尽管TC D 尚不能替代栓塞治疗前的脑血管造影， 但因其具有无创、简捷、重复性好等优点，能实时显示颅内血流动力学参数，有利于病情随诊和筛选患者，因而对脑血管病诊断、疗效评 估有重要价值。 of outside end; next wipe to sampling of parts, as Board head or top Department pipeline, then from tube head Shang carefully to will swab child into--will its all heap into until tube Central. Sterilization bags: bags must be purchased and sterilization of used only tear heads, providing local opened her bag, place the sample in, then roll up at the top of the bag, solid cord in prison; the bottom should be folded twice, so that the cord will not penetrate the plastic bags allow sample disclosure. When the sample collection, sample collection as well as conditions such as the temperature of the product, when, together with spike marks, samples, records together into the Inspector's notes, sample sample additional samples can be collected from sample number, date, number, and other identifying information for the first person to differentiate. When sterile samples collected, and one of the most important rule is: never contaminated the sample. Need samples to collect all the additional samples collected very carefully to ensure that no violations of this rule. Second, the microbiological characteristics of the sampling programme is a small sample of test results illustrate a large number of food hygiene, so that the representativeness of the sample for analysis is essential, that is, sample number, size and nature of major impact on the results. To ensure the representativeness of the sample, first a scientific sampling programme, then use appropriate sampling techniques and sample preservation and transport keep samples in their original condition. Whatever the methodfor urgent air dryer drying (on the kamaboko). (3) measuring glassware should be naturally drain cannot be baked in the oven. Glassware storage to provide storage, four in test case, to secure, high, great instruments in it. Required for long-term preservation of grinding pad between the instruments in a piece of paper, so as to avoid a long stick. Section II national standard specifications of the experimental laboratory water GB/T6682-1992 water for analytical laboratory specifications and test methods of chemical analysis of water and inorganic trace analysis, experiments are divided into 3 levels: level water, secondary, tertiary water. Analysis laboratory water should meet Xia table by column specifications: project a level two level three level pH value range (25 ?)--5.0-7.5 conductivity rate (25 ?), mS/m ? 0.01 ? 0.10 ? 0.50 can oxidation material *to (O) meter+,mg/L-? 0.08 ? 0.4 sucking photometric (254nm,1cm light drive) ? 0.001 ? 0.01-evaporation residue (105 ? ? 2 ?), mg/L-? 1.0 ? 2.0 soluble Silicon *to (SiO2) ? 0.01 ? 0.02 meter+,mg/L-section III solution the general concepts and preparation of a solution, solution definition and characteristics are two substance formed by the mixture of two or more (mixture). These substances are even at the molecular level, that spread reached the molecular level. Solution is part of the chemical composition and physical properties of the same mixture of a homogeneous system. Classification divides according to the aggregation solution, solution gas, liquid solution (often called liquid solution) and solid solution (also known as solid solution solid solution). Solution the term traditionally refers to the liquid solution. Formed by means of a liquid solution: gases dissolved in liquids, solids dissolved in liquid and