【作者】 李晓英；

【导师】 蒋国平；

【作者基本信息】 浙江大学 ， 儿科学， 2010， 硕士

【摘要】 研究背景与目的：右心功能评价在小儿先天性及后天获得性心脏病的诊疗中具有非常重要的价值。组织多普勒成像(tissue Doppler imaging, TDI)是近年来发展起来的超声新技术,心肌做功指数(myocardial performance index, MPA)又称为Tei指数,被认为是定量评估右心室整体功能的敏感而可靠的指标。本研究采用基于TDI技术的定量组织速度成像(quantitative tissue velocity imaging, QTVI)方法,测量216例正常小儿三尖瓣环运动速度参数及时间参数,旨在建立不同年龄组三尖瓣环QTVI速度参数及Tei指数的正常值范围,探讨年龄、心率、体表面积、三尖瓣环径等因素对其影响,并对QTVI-Tei及PWD-Tei值进行比较。资料与方法：2009年11月至2010年3月间在我院就诊的216例正常小儿,按年龄段将其分成7组：<1个月组、1个月～组、6个月～组、1岁～组、3岁～组、6岁～组、9-12岁组。采用美国GE公司Vivid 7和Vivid 7 Dimention彩色多普勒超声诊断仪,探头频率为1.5～8.0MHz,配有Echopac工作站、QTVI图像分析与后处理软件。脉冲多普勒于心尖四腔切面记录三尖瓣口血流频谱,胸骨旁右室流出道长轴切面记录右室流出道血流频谱；QTVI模式下,采集心尖四腔切面及心尖右心两腔切面各3个连续心动周期的动态图像,储存于硬盘后脱机分析。QTVI取样点分别置于三尖瓣前瓣、后瓣及隔瓣与三尖瓣环连接处,获取三尖瓣环运动速度一时间曲线,分别测量三个位点的收缩期峰值速度(Sa)、舒张早期峰值速度(Ea)、舒张晚期峰值速度(Aa),计算Ea／Aa值、E／Ea值。在脉冲多普勒血流频谱中测量三尖瓣口血流A波终末至下一E波起始的间期(a)及右室流出道血流的起止间期(b),a-b即代表了等容收缩时间(ICT)与等容舒张时间(IRT)之和,(a-b)／b为PWD-Tei指数。在心尖四腔切面QTVI模式下,取样点置于三尖瓣前瓣与三尖瓣环连接处,获取三尖瓣环运动速度一时间曲线,以心电图QRS波起点至下一Ea波起始的间期为a,以Sa波的起止间期为b,a-b代表了ICT与IRT之和,(a-b)／b即为QTVI-Tei指数。结果：(1)三尖瓣环前瓣、后瓣及隔瓣附着点处Sa、Ea均以<1个月组为最低,三个位点平均值为：Sa(5.61±1.12)cm／s,Ea(7.33±2.12)cm／s,随年龄逐渐增长,在1岁～组前增长较明显。前瓣及后瓣附着点处Ea/Aa在<1个月组比值小于1(前瓣附着点0.97±0.29,后瓣附着点0.91±0.26),其余组比值大于1,3岁～组前随年龄逐渐增大。各位点E／Ea值在1岁～组前随年龄增长而下降。(2)三尖瓣环前瓣、后瓣及隔瓣附着点处的Sa、Ea及Aa值均以前瓣附着点处最高,后瓣附着点处次之,隔瓣附着点处最低(P<0.05)。(3)相关分析显示三尖瓣环各位点Sa、Ea、Ea／Aa与年龄、体表面积、三尖瓣环径呈正相关,而Aa、E／Ea与上述因素呈负相关,Sa、Ea、Ea／Aa与心率呈负相关,而Aa、E／Ea与心率呈正相关。多因素回归分析提示三尖瓣环径是Sa、Ea／Aa和E／Ea的主要影响因子,是Ea的独立影响因子,心率是Aa的独立影响因子。(4)QTVI-Tei和PWD-Tei指数在<1月组较高(QTVI-Tei=0.39±0.03,PWD-Tei=0.38±0.05),与相邻组间有显著性差异(P<0.05),其余相邻组间无显著性差异。(5)216例小儿平均QTVI-Tei=0.37±0.05,PWD-Tei=0.35±0.05,前者略大于后者(P<0.05),两者相关系数r=0.594。(6)相关分析显示QTVI-Tei指数与年龄、体表面积和三尖瓣环径呈弱相关(r分别为0.300、0.249、0.170,P<0.05),PWD-Tei指数与年龄呈弱相关(r=0.176,P<0.05),两者与心率均不相关,多因素回归分析提示两者均受年龄影响。结论：(1)正常小儿三尖瓣环QTVI速度参数和QTVI-Tei指数随年龄增长而变化,以婴儿时期变化最为明显。本研究不同年龄组三尖瓣环直径、三尖瓣环QTVI速度参数及右室Tei指数可作为0～12岁小儿正常参考值。(2)正常小儿三尖瓣环运动速度不对称,以三尖瓣环前瓣附着点处的瓣环运动速度最快,该测量位置操作方便,不受室间隔和二尖瓣环运动影响,可能是比较理想的QTVI测量点。(3)三尖瓣环QTVI速度参数能区分收缩与舒张功能,时间参数Tei指数评价的是心脏的整体功能,两者相结合能更好地评价小儿右室功能。更多还原

【Abstract】 Background and Objective:It’s important to assess right ventricular (RV) function in congenital and acquired cardiac abnormalities in children. Tissue Doppler imaging (TDI) and Tei index have been recognized as sensitive and reliable methods in quantitative assessment of global RV function. In this study, we used quantitative tissue velocity imaging (QTVI) which derived from TDI to measure velocity and time intervals in tricuspid annulus in 216 normal children. We aimed to evaluate the effects of age, heart rate (HR), body surface area (BSA) and tricuspid valve annulus diameters (TAD) on the QTVI velocity parameters and QTVI-Tei index, and to compare the Tei index by the two methods of QTVI and pulsed wave Doppler (PWD).Methods:A total of 216 normal children were enrolled in this study, who took the regular health care visits in our hospital from November 2009 to March 2010. We divided them into 7 groups:under 1 month of age group,1 month-of age group,6 months-of age group,1 year-of age group,3 years-of age group,6 years-of age group and 9-12 years of age group. GE Vivid 7 and Vivid 7 dimension color Doppler scanners with 1.5-8.0 MHz transducers were used to detect the above children, which could analyze and post-process QTVI images with Echopac workstation.Transtricuspid flow velocity during early diastole (E) and late diastole (A) were measured by PWD in standard apical four-chamber view. RV outflow tract wave by PWD was recorded in parasternal long axis view of outflow tract. The images from standard apical four-chamber view and apical two-chamber view of right heart were recorded for three cardiac cycles.The QTVI sample volume was set at tricuspid annulus of anterior (AAP), septal (SAP) and posterior (PAP) attachment points to acquire speed-time curve. Peak systolic velocity (Sa), peak early (Ea) and late (Aa) diastolic velocity of tricuspid annulus were measured, and Ea/Aa and E/Ea ratio was calculated as well. PWD a component was measured from the trailing edge of the PWD tricuspid flow late diastolic A wave to the leading edge of the subsequent PWD tricuspid flow early diastolic E wave. The b component for the PWD was measured from the leading edge to the trailing edge of the PWD RV outflow tract tracing. The Tei index determined by PWD method was calculated as (a-b/b). QTVI a component was measured from the starting point of QRS wave in ECG to the leading edge of the subsequent early diastolic tricuspid annular QTVI Ea wave. The b component was measured from the leading edge of the systolic tricuspid annular QTVI Sa wave to the trailing edge of the Sa wave. The Tei index determined by QTVI method was calculated as (a-b/b).Results:(1) Sa and Ea were the lowest in children under 1 month of age group [the mean value of AAP, PAP and SAP:Sa (5.61±1.12)cm/s, Ea (7.33±2.12)cm/s]; The above two values increased with age and more rapidly at less than 1 year-of age group. The ratio of Ea/Aa from AAP and PAP were both less than 1 at the age of under 1 month (AAP:0.97±0.29, PAP:0.91±0.26), while more than 1 at other ages. It increased with age before 3 years-of age. E/Ea from all positions decreased with age before 1 year-of age.(2) Sa, Ea and Aa were the lowest from the location of SAP, and followed by those from PAP and AAP (P＜0.05).(3) Sa, Ea, Aa, Ea/Aa and E/Ea correlated significantly with age, HR, BSA and TAD. Multivariate regression analysis showed that TAD was the main factor that influenced Sa, Ea/Aa and E/Ea, and it was the independent factor that influenced Ea at tricuspid annulus. HR influenced Aa independently.(4) QTVI-Tei index and PWD-Tei index were both higher in age group of under 1 month(QTVI-Tei=0.39±0.03, PWD-Tei=0.38±0.05)than those in the group of 1 month-of age (P＜0.05).(5) Overall average Tei index values in RV by the two methods were:QTVI-Tei= 0.37±0.05 and PWD-Tei= 0.35±0.05. There was statistically significant difference between them (P<0.05), the correlation coefficient between them was 0.594.(6) Correlation analysis showed age, BSA and TAD had significant effects on the QTVI-Tei index, and age had significant effect on PWD-Tei index. Multivariate regression analysis revealed both QTVI-Tei index and PWD-Tei index were significantly affected by age.Conclusions:(1)QTVI velocity parameters and QTVI-Tei index developed with age in childhood, and it developed most rapidly during the infant period. This study established the normal values of QTVI velocity parameters of tricuspid annulus and RV Tei index in children. (2)There was asymmetry in the tricuspid annular motion. The AAP attachment might be an appropriate point to study the motion of tricuspid annulus because it had the fastest velocity, and it was easy to acquire; furthermore, it was not influenced by mitral annulus and septum.(3)QTVI velocity parameters can distinguish between systolic and diastolic function. Tei index is a feasible approach to assess global RV function. We suggest using QTVI velocity parameters together with Tei index to assess RV function in children.更多还原