速度向量成像技术评价脑梗死患者颈总动脉管壁运动的初步研究

目的应用速度向量成像（VVI）技术初步探讨脑梗死患者颈总动脉管壁短轴方向运动速度、应变及应变率的特点。方法试验组27例脑梗死患者，对照组25例正常人，VVI技术测量颈总动脉管壁短轴方向各壁的收缩期最大径向运动速度（Vs）、最大切向应变（Smax）及最大切向应变率（SRmax）。结果对照组颈总动脉各壁间（除前壁与外侧壁间）Vs两两比较差异均有显著性意义（P〈0．05），前壁、外侧壁Vs高于内侧壁、后壁。脑梗死组Vs各壁之间差异无显著性意义（P〉0．05）。脑梗死组与对照组各壁间Smax、SRmax比较差异均无显著性意义（P〉0．05）。颈总动脉各壁（除后壁外）Vs均小于正常对照组（P〈0．05）；两组间对应各壁Smax差异无显著性意义（P〉0．05）；脑梗死组颈总动脉各壁SRmax均小于正常对照组（P〈0．05）。结论VVI技术可用于颈总动脉管壁运动速度、应变及应变率的分析。     

速度向量成像技术评价正常人颈总动脉内膜力学状态的初步研究

目的 应用速度向量成像(VVI)技术,初步探讨正常人颈总动脉管壁长轴方向运动速度、应变及应变率的特点及关系.方法 试验组32例正常人,用VVI技术测量颈总动脉管壁长轴方向前壁、后壁的收缩期及舒张期最大峰值运动速度(Vs)、最大切向应变(Smax)及最大切向应变率(Srmax)之间的关系.结果 正常人颈总动脉前壁与后壁长轴方向运动速度比较无明显差异(P>0.05),前壁与后壁应变比较无明显差异(P>0.05),前壁与后壁应变率比较无明显差异(P>0.05),颈静脉搏动对于颈动脉前壁的影响不明显,近心端分析点与远心端分析点速度、应变及应变率均无明显差异(P>0.05).结论 VVI技术可用于颈总动脉管壁运动速度、应变及应变率的推测分析.     

速度向量成像技术评价正常人颈总动脉管壁运动力学状态

目的 应用速度向量成像(VVI)技术分析正常人颈总动脉(CCA)短轴方向管壁运动和弹性参数特点及其与影响因素间的关系. 方法 健康志愿者40名,采用Siemens Acuson Sequoia 512彩色多普勒超声诊断仪采集连续3个心动周期的CCA动态短轴二维图像,分析右侧CCA管壁短轴方向6个节段(前壁、后壁、前外侧壁、前内侧壁、后外侧壁、后内侧壁)的运动、弹性及其衍生参数的特点,并分析这些参数间及其与相关影响因素间的关系. 结果 各侧壁的弹性相关参数差异无统计学意义(P>0.05);运动相关参数(除速度达峰时间)差异有统计学意义(P<0.05),即外侧壁和前壁明显高于后壁和内侧壁.年龄及内-中膜厚度与部分弹性参数及部分运动参数呈负相关(P<0.05).心率与部分弹性参数及部分运动参数呈正相关(P<0.05).弹性与运动参数间呈正相关(P<0.05),弹性及运动参数达峰时间呈正相关(P<0.05). 结论 VVI技术可用于研究正常人CCA管壁的运动力学特点及其与影响因素之间的关系.     

速度向量成像技术评价妊娠高血压综合征颈总动脉长轴管壁运动的初步研究

目的 应用速度向量成像技术(VVI)评估妊娠高血压综合征(妊高征)患者颈总动脉管壁径向运动速度峰值、应变及应变率的特点,初步探讨该技术在评估妊高征血管机械特性方面的临床应用价值.方法 28例妊高征患者(妊高征组),34例正常妊娠者(对照组),应用VVI技术测量分析右侧颈总动脉长轴切面前壁及后壁的收缩期径向运动速度峰值、应变及应变率.结果 妊高征组颈总动脉前壁及后壁收缩期径向运动速度峰值较正常妊娠组明显减低[(0.22±0.09)cm/s对(0.29±0.09)cm/s,P<0.01;(0.24±0.10)cm/s对(0.34±0.13)cm/s,P<0.01],其前、后壁的应变及应变率也较正常妊娠组明显降低r应变:(8.50±4.92)%对(12.2±6.21)%,P<0.01;(10.11土5.02)%对(14.21±6.48)%,P<0.05;应变率:(1.62±1.14)s~(-1)对(2.24±1.13)s~(-1),P<0.05;(1.91±0.99)s~(-1)对(2.45±1.02)s~(-1),P<0.05].结论 VVI技术可用于评价妊高征患者血管壁力学特性.     

速度向量成像技术评价脑梗死患者颈总动脉弹性变化的初步研究

目的 初步探讨速度向量成像(VVI)技术评价脑梗死患者颈总动脉弹性变化的临床应用价值.方法 应用VVI技术分别检测54例脑梗死患者、51例非脑梗死患者颈总动脉短轴切面各壁的收缩期最大运动速度(Vs)、最大应变(Smax)及最大应变率(SRmax)并进行分析.结果 两组内颈总动脉管壁的Vs、Smax 和SRmax在各壁之间差异无统计学意义(P>0.05);两组间各壁的Vs和Smax差异无统计学意义 (P>0.05);脑梗死组各壁的SRmax均小于非脑梗死组,差异有统计学意义(P<0.05).结论 速度向量成像技术可以准确检测颈总动脉的弹性变化,为临床定量评价脑梗死患者颈总动脉弹性提供一种新方法.     

速度向量成像技术对正常人颈总动脉管壁形变特征的初步研究

目的 应用速度向量成像（VVI） 技术初步研究正常人颈总动脉管壁形变特征.方法 超声采集并动态存储47 例正常人颈总动脉长轴及短轴二维灰阶图像.应用VVI技术观察颈总动脉管壁纵向和周向应变及应变率曲线,以同步记录心电图为时相对照,测量颈总动脉管壁收缩期纵向和周向峰值应变及应变率.结果 正常人颈总动脉后壁近心点、中点及远心点间的收缩期纵向峰值应变及峰值应变率差异无统计学意义（P〉0.05）;正常人颈总动脉短轴管壁各节段间收缩期周向峰值应变及应变率差异无统计学意义（P〉0.05）.结论 正常人颈总动脉管壁收缩期纵向峰值应变及应变率沿颈总动脉后壁长轴分布基本均匀,收缩期周向峰值应变及应变率在颈总动脉管壁短轴方向分布亦基本均匀.     

速度向量成像技术评价颈部放疗影响颈总动脉管壁运动的初步研究

目的应用速度向量成像技术定量分析颈总动脉壁运动,评估颈部放疗对颈总动脉管壁运动的影响。方法利用超声速度向量成像技术对14例颈部放射治疗患者(研究组)和33例正常健康人(对照组)进行检查,分别测量两侧颈总动脉前壁、后壁、内侧壁和外侧壁,并对动脉壁运动进行观察和测量,计算血管壁各点速度向量值。结果研究组与对照组颈总动脉壁运动应变值除右侧颈总动脉后壁和外侧壁外,其余测量点血管壁应变值之间均存在显著差异(P0.05)。结论速度向量成像技术为血管壁功能的评价提供了新的方法和指标,能更早地发现颈部放疗对颈总动脉的损伤。     

速度向量成像技术应用现状及前景

速度向量成像技术(VVI)是新近发展起来的一种无创性定量评价心肌功能的超声技术,能形象、直观地显示心肌纤维在纵向、径向和环向上的运动特征,能够无创、定量、准确和快速评价心肌运动的协调性.VVI可以灵敏反映心肌功能受损早期的舒张功能改变,观测原发性心肌病、先天性心脏病、糖尿病、尿毒症性心脏病的应变率与应变的变化,有助于早期诊断与观察疗效.因此,本文就速度向量成像的研究与应用现状作一综述.     

速度向量成像技术对正常成人颈总动脉弹性特点的初步研究

目的应用速度向量成像(VVI)技术初步研究正常成人颈总动脉短轴的弹性特点。方法选取正常成人20例,采集距右侧颈总动脉分叉1 cm处短轴切面的动态图像,应用VVI技术对图像进行定量分析,测量右侧颈总动脉管壁短轴收缩期峰值运动速度、应变及应变率,绘制其管壁短轴运动速度、应变及应变率曲线。结果正常成人右侧颈总动脉短轴的运动速度、应变及应变率曲线均呈规则的分布一致变化;三维图均呈规律、色彩交替的彩色波峰、波谷变化,且波峰、波谷的峰值趋于一致。正常成人右侧颈总动脉短轴管壁6个侧壁收缩期峰值运动速度、应变及应变率比较,差异均无统计学意义。结论正常成人颈总动脉短轴收缩期峰值运动速度、应变及应变率在颈总动脉管壁短轴方向分布基本均匀。     

超声速度向量成像评价兔左心室收缩功能与心肌细胞凋亡相关性的研究

变率绝对值逐渐减小,两两比较有统计学差异(P<0.05);(2)心肌细胞凋亡率和左室应变率相关性分析:B、C、D三组心肌细胞凋亡率明显高于A组(P<0.01),且三组之间比较,差异有统计学意义(P<0.05);四组之间应变率与心肌细胞凋亡率呈显著正相关(r1＝0.81,r2＝0.79,P<0.01).结论 超声速度向量成像技术可以早期定量诊断心力衰竭过程中的心肌损伤.     

速度向量成像技术评价颈总动脉粥样硬化斑块力学状态的研究

目的 应用速度向量成像(VVI) 技术评价颈总动脉壁粥样硬化斑块运动特性及斑块力学的临床价值.方法 对36例动脉粥样硬化斑块患者和对照组30例正常人双侧颈总动脉进行超声检查;并检测出颈总动脉内中膜厚度(IMT),结合同步心电图描记,取颈总动脉长轴、短轴二维图像进行动态存储,运用VVI软件进行脱机分析,计算颈动脉壁粥样斑块部位的运动速度、应变和应变率,并与正常组动脉壁运动参数进行比较.结果颈总动脉粥样斑块处运动速度、应变及应变率低于无斑块处;斑块基底部速度、应变及应变率低于斑块表面;斑块组颈动脉IMT及运动速度均高于正常对照组(P<0.5),软斑块收缩期最大运动速度、最大应变率分别高于硬斑块组,肩部运动速度、应变率高于帽顶部(P<0.5).结论 VVI 技术可用于颈总动脉管壁斑块运动速度、应变及应变率的分析,为研究颈总动脉斑块形成机理和稳定性,提供新的方法.     

二维应变与组织多普勒评价心肌应变的对比研究

目的评价新的超声软件二维应变（2DS）在定量心肌应变与应变率中的价值。 方法采集18例正常人与15例前壁心肌梗死（心梗）患者心尖二腔长轴二维灰阶与组织多普勒（TVI）动态图，用2DS与TVI2种方法分别测量各节段心肌长轴峰值收缩速度（Vs）、峰值收缩应变（S）及应变率（Sr）并做对比；采集乳头肌水平短轴二维灰阶动态图，应用2DS测量各节段心肌径向Vs、S、Sr，对比正常与梗死节段心肌测值。 结果2DS所测正常与心梗患者的长轴Vs、S及Sr均与TVI测值无差异（P〉0．05）；2DS所测左室乳头肌水平各段心肌的径向Vs、S及Sr在正常组无差异（P〉0．05），而心梗组的梗死节段测值明显低于非梗死节段（P〈0．01），并明显低于正常组相应节段（P〈0．01）。 结论2DS可准确定量节段心肌运动速度、应变与应变率，可通过测量心肌长轴与径向的上述参数用于评价心肌功能。     

In Vivo Blood Velocity Vector Imaging Using Adaptive Velocity Compounding in the Carotid Artery Bifurcation

Visualization and quantification of blood flow are considered important for early detection of atherosclerosis and patient-specific diagnosis and intervention. As conventional Doppler imaging is limited to 1-D velocity estimates, 2-D and 3-D techniques are being developed. We introduce an adaptive velocity compounding technique that estimates the 2-D velocity vector field using predominantly axial displacements estimated by speckle tracking from dual-angle plane wave acquisitions. Straight-vessel experiments with a 7.8-MHz linear array transducer connected to a Verasonics Vantage ultrasound system revealed that the technique performed with a maximum velocity magnitude bias and angle bias of –3.7% (2.8% standard deviation) and –0.16° (0.41° standard deviation), respectively. In vivo, complex flow patterns were visualized in two healthy and three diseased carotid arteries and quantified using a vector complexity measure that increased with increasing wall irregularity. This measure could potentially be a relevant clinical parameter which might aid in early detection of atherosclerosis.     

Combined Vector Velocity and Spectral Doppler Imaging for Improved Imaging of Complex Blood Flow in the Carotid Arteries

Color flow imaging and pulsed wave (PW) Doppler are important diagnostic tools in the examination of patients with carotid artery disease. However, measurement of the true peak systolic velocity is dependent on sample volume placement and the operator's ability to provide an educated guess of the flow direction. Using plane wave transmissions and a duplex imaging scheme, we present an all-in-one modality that provides both vector velocity and spectral Doppler imaging from one acquisition, in addition to separate B-mode images of sufficient quality. The vector Doppler information was used to provide automatically calibrated (angle-corrected) PW Doppler spectra at every image point. It was demonstrated that the combined information can be used to generate spatial maps of the peak systolic velocity, highlighting regions of high velocity and the extent of the stenotic region, which could be used to automate work flow as well as improve the accuracy of measurement of true peak systolic velocity. The modality was tested in a small group (N = 12) of patients with carotid artery disease. PW Doppler, vector velocity and B-mode images could successfully be obtained from a single recording for all patients with a body mass index ranging from 21 to 31 and a carotid depth ranging from 16 to 28 mm.     

Two-Dimensional Strain Imaging of Controlled Rabbit Hearts

Ultrasound strain imaging using 2-D speckle tracking has been proposed to quantitatively assess changes in myocardial contractility caused by ischemia. Its performance must be demonstrated in a controlled model system as a step toward routine clinical application. In this study, a well-controlled 2-D cardiac elasticity imaging technique was developed using two coplanar and orthogonal linear probes simultaneously imaging an isolated retroperfused rabbit heart. Acute ischemia was generated by left anterior descending (LAD) artery ligation. An excitation-contraction decoupler, 2,3-butanedione monoxime, was applied at a 4-mM concentration to reversibly reduce myocardial contractility. Results using a single probe demonstrate that directional changes in the in-plane principal deformation axes can help locate the bulging area as a result of LAD ligation, which matched well with corresponding Evans Blue staining, and strains or strain magnitude, based on principal stretches, can characterize heart muscle contractility. These two findings using asymmetric displacement accuracy (i.e., normal single-probe measurements with good axial but poor lateral estimates) were further validated using symmetric displacement accuracy (i.e., dual-probe measurements using only accurate axial tracking estimates from each). However, the accuracy of 2-D cardiac strain imaging using a single probe depends on the probe's orientation because of the large variance in lateral displacement estimates. (E-mail: cxjia@umich.edu)     

速度向量成像技术定量评价蒽环类药物心肌毒性

[目的]探讨应用速度向量成像(VVI)技术评估蒽环类药物(ATC)早期心肌毒性的应用价值.[方法]对30例淋巴瘤患者在应用表阿霉素化疗前及化疗后疗程累计剂量为150 mg、300mg、450mg时进行常规超声心动图及VVI参数比较,并与32例正常人作对照.[结果]常规超声心动图测量的病例组各期的左室舒张末内径(LVEDD)、左室收缩末内径(LVESD)及左室射血分数(EF),左室短轴缩短率(FS)与对照组比较差异均无统计学意义.VVI技术测量参数在用药后在累计剂量达300 mg/m2时,左室各节段应变及应变率曲线出现低平且形态不规则,收缩期最大速度(Ssv)、收缩期应变峰值(SSE)及应变率(SSR)均降低.当累积剂量达450 mg/m2时,各值差异显著,有统计学意义(P＜0.05).[结论]与传统二维超声心动图相比,VVI技术可以较早期,更敏感、无创评价蒽环类药物对肿瘤患者化疗时的左心功能损害.     

Common Carotid Artery Flow Measured by 3-D Ultrasonic Vector Flow Imaging and Validated with Magnetic Resonance Imaging

Ultrasound (US) examination of the common carotid artery was compared with a through-plane magnetic resonance imaging (MRI) sequence to validate a recently proposed technique for 3-D US vector flow imaging. Data from the first volunteer examined were used as the training set, before volume flow and peak velocities were calculated for the remaining eight volunteers. Peak systolic velocities (PSVs) and volume flow obtained with 3-D US were, on average, 34% higher and 24% lower than those obtained with MRI, respectively. A high correlation was observed for PSV (r = 0.79), whereas a lower correlation was observed for volume flow (r = 0.43). The overall standard deviations were ±5.7% and ±5.7% for volume flow and PSV with 3-D US, compared with ±2.7% and ±3.2% for MRI. Finally, the data were re-processed with a change in the parameter settings for the echo-canceling filter to investigate its influence on overall performance. PSV was less affected by the re-processing, whereas the difference in volume flow between 3-D vector flow imaging and MRI was reduced to ?9%, and with an improved overall standard deviation of ±4.7%. The results illustrate the feasibility of using 3-D US for precise and angle-independent volume flow and PSV estimation in vivo.