【作者】 李成；

【导师】 宋伟；

【作者基本信息】 蚌埠医学院 ， 影像医学与核医学， 2012， 硕士

【摘要】 研究背景：原发性高血压（essential hypertension， EH）是指以血压升高为主要临床表现的一种疾病，约占高血压患者的95%。由多种致病因素通过复杂的发病机制综合作用所引起的一种具有遗传倾向的疾病，是危害人类健康的多发病。现已证明，血压升高是我国心血管病最重要的危险因素。作为靶器官之一的心脏与高血压存在密切的关系，其主要危害是心脏负荷的增加导致心脏不良重构，这种不良重构主要是“左室重构”，这种重构的过程必然也导致心脏功能的改变。因此，监测高血压所致的心室功能异常对于疾病的预防与治疗显得尤为重要。斑点追踪显像技术（speckle tracking imaging，STI）是在应变及应变率显像的基础上发展而来的一种新技术，通过追踪二维超声图像上的斑点获得心肌的组织速度、应变、应变率来分析心肌的运动。它不依赖于多普勒原理，无角度依赖性[2-3]，因而比组织多普勒成像有更大的优越性。目的：本研究旨在应用超声斑点追踪显像技术（speckle tracking imaging，STI），通过对原发性高血压患者和正常对照者左室纵向收缩期峰值应变（systolic peaklongitudinal strain，SLs）指标的分析来探讨这种新技术评价原发性高血压患者左室纵向收缩功能的临床价值，为临床评价原发性高血压患者心脏功能提高依据。资料与方法：40例正常对照组，60例高血压病组，30例高血压伴心力衰竭组。采用GE Vivid7超声诊断仪，M4S探头，探头频率为1.7～3.4MHz，帧频为50～90帧/秒，V3三维心脏探头，探头频率为2.0～4.0MHz。受检者静坐10分钟开始检查，检查时连接心电图导联，取左侧卧位，平静呼吸。获取各切面图像，存储机器中，然后脱机分析，应用机器内置软件自动分析。取标准二维灰阶图像，测量左房内径（LAD）、左室舒张末期内径（LVEDd）、室间隔舒张末厚度（IVSTd）及左室后壁舒张末厚度（LVIDd），另应用M型超声测量左室射血分数（LVEF），应用脉冲多普勒超声：心尖四腔切面记录二尖瓣血流频谱，测定舒张早期峰值流速E、舒张晚期峰值流速A及E/A。通过实时三平面超声心动图Simpson’s法获取左心室舒张末容积（LVEDV）、左心室收缩末容积（LVESV）、左室射血分数（LVEF）、每搏量（SV）、心输出量（CO）等，应用仪器内置AFI，首先选定心尖左室长轴切面，在收缩末期选取两侧瓣环和心尖三点的左室心内膜，软件自动跟踪感兴趣区内心肌的运动，并将图像中的各室壁分为基底段、中间段和心尖段，共计6个节段，对每个室壁节段给出分析结果，即成功节段“√”及不成功节段“×”，自动测量各节段心肌的纵向收缩期峰值应变（（SLs）及该切面平均纵向收缩期峰值应变（GLS）。同法依次分析左室心尖四腔心切面及心尖两腔切面，最后机器给出心尖位三个切面共18个节段SLs、各切面平均应变（GLS–LAX、GLS-A4C、GLS-A2C）及左室心肌平均纵向收缩期峰值应变（GLS-Avg），软件自动给出该受检者应变牛眼图，记录各项数据并进行统计学分析。结果：1、常规超声心动检查：高血压组、高血压伴心衰组与正常对照组常规超声心动图测量指标比较：高血压组和高血压伴心衰组与正常对照组比较左房内径增大，差异有统计学意义（P＜0.05），高血压左心室肥厚组（LVH）与正常对照组、高血压非左心室肥厚组（nLVH）比较室壁增厚、LVMI增高，差异均有统计学意义（P＜0.05），高血压伴心衰组与正常对照组、高血压比较LVEF明显减低，差异有统计学意义（P＜0.05），高血压组、高血压伴心衰组与正常对照组比较，E峰降低，E/A值减小，差异有统计学意义（P＜0.05）2、实时三平面超声心动图检查：高血压伴心衰组与正常对照组、高血压组比较EDV、ESV升高SV、LVEF减低，差异有统计学意义（P＜0.05）3、超声斑点追踪成像技术检查：3.1正常对照组左心室心肌SLs：本组左心室各节段在心动周期中的SLs曲线为双峰曲线，随着心肌收缩，应变从0值向负值发展，T波终末（收缩末期）前后达最大负值；舒张早期心肌迅速纵向伸长，应变值从最大负值向0值靠近，并在舒张晚期心房收缩形成小的负向峰后向正向发展，在下一心动周期的R波顶点前后达最大正值，最大SLs为负值。同一室壁不同节段比较，从基底部到心尖部SLs绝对值逐步递增，呈现为一定的“极向性”即基底段＜中间段＜心尖段。3.2高血压组和正常对照组SLs比较：高血压非左心室肥厚组（nLVH）与正常对照组相比，本组左室各节段心肌SLs绝对值均减低，但仅9.6%节段差异有统计学意义（P＜0.05），本组左室心肌24.2%节段存在收缩后收缩现象（即达峰时间延长，SLs峰值在等容舒张期），与正常对照组相比较差异有统计学意义（P＜0.05）。高血压左心室肥厚组（LVH）与正常对照组、高血压非左心室肥厚组（nLVH）相比，本组左室心肌16.7%节段SLs、左室各切面SLs及左室整体SLs峰值显著减低，差异有统计学意义（P＜0.05）。本组左室心肌26.9%节段存在收缩后收缩现象，与正常对照组相比较差异有统计学意义（P＜0.05），本组心肌3.7%节段存在矛盾运动现象（即SLs曲线在收缩期均为正值，曲线均在应变零基线以上），与正常对照组、高血压非左心室肥厚组（nLVH）相比较差异均有统计学意义（P＜0.05）。3.3高血压伴心衰组和正常对照组、高血压组SLs比较：本组左室心肌61.1%节段SLs、左室各切面SLs及左心室整体SLs峰值显著减低，与正常对照组、高血压组比较差异有统计学意义（P＜0.05），本组内左室心肌各节段SLs、左室各切面SLs及左室整体SLs峰值绝对值随LVEF的减低而逐渐减低，与LVEF相关性良好。本组左室心肌53.7%节段存在收缩后收缩现象，与正常对照组、高血压组相比较差异有统计学意义（P＜0.05），本组心肌22.2%节段存在矛盾运动现象，与正常对照组、高血压组相比较差异有统计学意义（P＜0.05）。结论：1、斑点追踪显像技术（speckle tracking imaging，STI）可以准确的评价高血压患者左室长轴运动，比常规超声心动图、实时三平面超声心动图更准确性、更敏感性，而且不仅可以评价左室长轴整体运动还可以评价各节段的运动。2、斑点追踪显像技术，没有角度依赖性，可重复性好，操作过程相对简便，并通过美国超声心动图学会（ASE）检测可用于临床，并被移植于GEVV7中。更多还原

【Abstract】 Backgruond:With the ascending of the blood pressure as its main clinical manifestation, Essentialhypertension (EH) refers to a disease accounting for95%of patients with hypertension.As a frequently-occuring disease which can endanger human health,it results from thecombination of complex pathogenesis and has genetic tendency.High blood pressure hasbeen shown to be the most important risk factor of cardiovascular disease in China. As atarget organ, the heart is strongly related to hypertension，and its main detriment is thatthe extra load in the heart will lead to harmful myocardial remodeling, which is mianly"left ventricular remodeling",and this remodeling will inevitablely lead to changes incardiac function. Therefore, monitoring ventricular dysfunction caused by hypertensionis particularly important for the prevention and treatment.Speckle tracking imaging (speckle tracking imaging, STI) is a new technologyevolved upon the theory of strain and strain rate imaging. By tracking spots ontwo-dimensional ultrasound images the myocardial tissue velocity, strain, strain rate areobtained in order to analyze the myocardial motion.It isn’t based on Doppler principleand thus has no angular dependence, for this it has greater advantages than tissueDoppler imaging.Objective：This study was conducted to evaluate speckle tracking imaging (STI) in assessmentof left ventricular systolic function,by using STI to assay systolic peak longitudinalstrain(SLs) of both hypertensive patients and nomal contral group, so as to provideevidence for clinical evaluation of the cardiac function in hypertensive patients.Materials and Methods： Study population consisted of40normal subjects (control group),60hypertensivepatients(H group) and30hypertensive patients with heart failure(HHF group). Subjectsare examined using GE Vivid7Diasonograph, M4S probe, the probe frequency of1.7~3.4MHz, a frame rate of50to90frames/sec, V3-D heart probe, the probe frequencyof2.0~4.0MHz. Subjects sat10minutes to start checking, checked connection of ECG,took left lateral decubitus position and calm breathing. For each section image, stored inthe machine, and then made off-line analysis, the data was automaticly analyzed bybuilt-in software of the Diasonograph. Take the standard2-D gray-scale images,measureed left atrium dimension (LAD), left ventricular end-diastolic dimension(LVEDd), diastolic interventricularseptal thickness (IVSTd) and left ventricularend-diastolic wall thickness (LVIDd).Then M-mode Echocardiography was used tomeasure left ventricular ejection funcction (LVEF), Pulsed-wave Doppler of transmitralwere obtained form the apical four chamber view．The following parameters weremeasured：peak velocity of early rapid filling(E),peak Velocity of atrial filling(A) andthe ratio of E to A(E/A). Using real-time tree-plane echocardiography Simpson’smethod，the following parameters were measured：left ventricular end-diastolic volume(LVEDV), left ventricular end-systolic volume (LVESV),left ventricular ejectionfunction (LVEF), stroke volume (SV),cardiac output (CO),etc.. Using instrumentbuilt-in AFI, to start with the apical left ventricular long-axis view, selected theend-systolic three sides of the valve annulus and left ventricular endocardial apex, thesoftware automatically tracked the movement of myocardial region of interest, andimage was divided into basal segment of the wall, the middle segment and apicalsegments, a total of six segments, each wall segment of the analysis results were given,that a successful segment "√" and failed segment "×" automatic measurement of thelongitudinal myocardial systolic peak systolic strain ((SLs) and the average longitudinalsection peak systolic strain (GLS). In the same way left ventricular apical four-chamberview and apical two chamber view were analyzed. Finally the instrument provided18-bit three segments SLs of apical section, as well as the average strain (GLS-LAX,GLS-A4C, GLS-A2C) and left ventricular myocardial longitudinal systolic averagepeak strain (GLS-Avg)of each section. The software provided bull’s-eye plot of the subject automatically, and the data was recorded and analyzed statistically.Results:1. Conventional echocardiographyComparison of measurements among H gpoup, HHF group and the contral group:compared with the control group, left ventricular diameter increased significantly (P<0.05). Compared with the control group and no left ventricular hypertrophy （nLVH）group, the wall of left ventricular hypertrophy （LVH）group thickened, and LVMIincreased, the difference was statistically significant (P <0.05). LVEF of HHF groupwas significantly lower than that of both the contral group and H group (P <0.05).Compared with the control group, in both H group and HHF group E-wave reducted andE/A value decreased significantly (P <0.05)2. Real-time tri-plane echocardiography:Compared with the contral group and H group, EDV and ESV of HHF groupincreased while SV and LVEF reduced significantly.3. STI examination:3.1Left ventricular SLs of the contral group.The SLs curve of left ventricular cardiac cycle was a bimodal curve, accompanywith the myocardial contraction, strain valued from0to negative development, andreached the maximum negative value before and after the T-wave offset (end-systolic).In early diastole myocardium longated rapidly, strain valued from maximum negative to0, and began the positive development at the end-diastolic, then reached a maximumpositive value before and after the R wave peak in the next cardiac cycle,with themaximum SLs a negative value. Comparing different segments of the same wall, theabsolute value of SLs increased gradually from base to apex, rendered as a certain"polarity" that basal segment <middle section <apical segment3.2Comparison of SLs between H group and the contral groupCompared with the contral group, in the nLVH group the left ventricularmyocardium SLs absolute value of each segment were reduced, but only9.6%of thesesegments were significantly (P <0.05),24.2%ventricular segments of this grouppostsystoliely shortened(ie, peak time extened, SLs peak in the isovolumic relaxation period), compared with the control group the difference was statistically significant (P<0.05).Compared with the contral group and nLVH group, in the LVH group, SLs of16.7%segments of the left ventricular myocardial segments and each section of leftventricular as well as SLs peak of whole left ventricular, all reduced significantly (P<0.05).3.7%of the ventricular segments motioned discrepantly (ie, systolic curve SLswere positive, zero-strain curved above baseline), compared with control group, andnLVH group, the differences were statistically significant (P <0.05).3.3Comparison of SLs between HHF group and the contral group,H groupSLs of61.1%segments of the left ventricular myocardial reduced significantlycompared with the contral group and H group (P <0.05). SLs of each segment and eachsection of left ventricular as well as SLs absolute peak value of whole left ventricular,all reduced as the reduction of LVEF, which showed a good correlation with LVEF.53.7%ventricular segments of this group postsystoliely shortened ignificantlycompared with the contral group and H group (P <0.05).22.2%of the ventricularsegments motioned discrepantly,compared with control group, and nLVH group, thedifferences were statistically significant (P <0.05).Conclusion:1. speckle tracking imaging (speckle tracking imaging, STI) can accurately assessleft ventricular long axis motion in patients with hypertension, it is more accurate andmore sensitive compared with conventional echocardiography and real-time tree-planeechocardiography. Furthermore, STI can not only evaluate the whole left ventricularlong axis movement but also can evaluate the movement of each segment.2. STI is superior to conventonal echocardiography for no angular independence, ithas high repeatability and relatively simple process of analysis. STI matched the requestof U.S. Society of Echocardiography (ASE) for clinical use,and was transplanted inGEVV7.更多还原