【作者】 方凌云；

【导师】 谢明星；

【作者基本信息】 华中科技大学 ， 影像医学与核医学， 2008， 博士

【摘要】 房间隔缺损是临床上常见的先天性心血管畸形,占先天性心脏病的25~30%。近年来,Duke大学研制的实时三维超声心动图技术广泛应用于临床,该技术能动态实时显示房间隔的形态学特征,能准确评判缺损类型、直径、面积,能全面显示缺损毗邻位置与空间关系,这对房间隔缺损的量化评价、心脏结构与血流动力学关系的理解、治疗方案的合理化决策具有重要意义。我们应用实时三维超声心动图技术对房间隔缺损面积的动态变化特征进行过研究,这项研究表明房间隔缺损面积在心动周期中呈明显的动态变化,随着心房收缩,房间隔缺损面积逐渐减小,至心室舒张末期达最小,然后在心室收缩期逐渐增加,至收缩末期达最大。房间隔缺损的这种动态变化特征的发生机制可能与瓣膜启闭引起的心房压力容积的变化有关,也有研究认为与室壁的位移有关。利用实时三维超声心动图在心脏三维动态成像方面的技术特点,我们认为该技术有可能在分析心房容积和房室瓣环空间位移上发挥优势,从而明确房间隔缺损动态变化的发生机制。对心脏舒缩运动引起的容积变化和室壁空间位置改变的三维阐释,势必有助于理解心肌舒缩引起的血流动力学变化与心脏结构变化的关系,在了解房间隔缺损面积动态特征机制的基础上,加强对心脏收缩力状态、负荷情况和疾病状态的关系的理解,更有助于临床诊断治疗的合理化决策。房间隔缺损时,左心房压力通常高于右心房,且右心室壁薄,顺应性良好,易于舒张,故常存在大量左向右分流,使右心系统容量负荷明显增加,必然不同程度地影响右心功能。房间隔缺损患者右心容积和功能的准确评价对患者病情估价、治疗决策、疗效监测和预后判断具有重要临床价值。心室造影、放射性核素显像、磁共振成像和CT轴位成像在评价心室容积和功能方面由于有创性、价格昂贵或某些禁忌症限制了其应用。超声技术具有无创、简捷、准确的优点,故成为临床应用中最常用的评价方法。然而右室形态极不规则,具有相对独立的流出道,肌小梁粗大,二维超声显像作为一种平面显像方法,在测定右心室容积和功能方面的价值有限。动态三维超声心动图可以用于右心容积的测定和右心功能的评价,但迄今为止该技术未能广泛应用于临床的主要原因在于从图像获取、数据处理、三维重建直到图像显示操作复杂、耗时。由于右心室结构的复杂性,对于房间隔缺损等右心容量负荷增加造成的右心室局部腔室的改变和重构了解的较少,而右室局部功能可早期反映右室功能变化及局部心肌运动异常,因此对右室容积和功能的评价应包括整体和局部功能的评价。对右室局部收缩功能的评价的超声技术有组织多普勒显像、声学定量技术、应变和应变率显像以及新近应用的速度向量显像等。这些技术主要通过对局部心肌位移和收缩速度的观测来评价心肌的局部收缩性能,较少对局部心肌的泵功能状态进行评价。实时三维超声心动图克服了上述超声技术在评价右室容积与功能方面的局限性,能够快速获取右室容积的动态影像,结合三维工作站的内膜检测功能,构建出不依赖几何模型假设的真实的右室腔立体图像,根据右心室形态学和功能学的特点将右室腔分为三部分,从而可获得各部分的容积变化信息,为评价右室局部泵功能提供了基础。本研究分为四部分:第一部分实时三维超声心动图评价正常人房间隔动态特性及其相关因素本研究对20例正常人行实时三维成像,结合三维数据工作站,分别于心动周期的P波顶点、R波顶点、T波起点、T波终点、T-P段测量房间隔的面积,于上述相同心动周期时相测量右心房容积及相对应时期的三尖瓣环运动位移距离,并与房间隔面积测值行相关分析。探讨应用实时三维超声心动图技术评价正常人房间隔动态变化规律及其相关因素。结果显示:①正常人房间隔面积在心动周期中面积变化率32.3%~55.8%,平均(50.7±6.2)%。随着心房收缩房间隔面积逐渐减小,至心室舒张末期达最小,然后在心室收缩期逐渐增加,至收缩末期达最大。②右心房容积及三尖瓣环运动位移曲线在心动周期中呈动态变化,房间隔面积的变化特性与其变化特性相同。③房间隔面积在P波顶点、R波顶点、T波起点、T波终点、T-P段测值与相对应右心房容积相关系数分别为0.78、0.79、0.83、0.91、0.84(P均<0.001),房间隔面积变化与三尖瓣环运动位移距离相关性良好,r值分别为0.61、0.68、0.73、0.66、0.60(P均<0.05)。第二部分实时三维超声心动图评价房间隔缺损面积动态特征机制的探讨本研究对28例房间隔缺损患者和28例正常对照者行实时三维成像,结合三维数据工作站,分别于心动周期的P波顶点、R波顶点、T波起点、T波终点、T-P段测量房间隔缺损的面积,于上述相同心动周期时相测量右心房容积及相对应时期的三尖瓣环运动位移距离,并与房间隔缺损面积测值行相关分析。比较正常对照组和房间隔缺损组右心房容积和三尖瓣环运动位移距离的变化。应用实时三维超声心动图长轴八平面法测量并比较正常对照组和房间隔缺损组右室射血分数。旨在通过分析右心房容积和三尖瓣环运动位移距离在心动周期中的变化规律以及房间隔缺损面积与其的关系,从而对房间隔缺损面积动态特征的机制加以探讨。结果显示:①房间隔缺损面积在心动周期中呈动态改变,缺损面积变化率40.4%~77.2%,平均(60.3±10.2) %。随着心房收缩,房间隔缺损面积逐渐减小,至心室舒张末期达最小,动态变化曲线达最低点;然后在心室收缩期逐渐增加,至收缩末期达最大,变化曲线达高峰。②右心房容积及三尖瓣环运动位移曲线在心动周期中呈动态变化,房间隔缺损面积的变化特性曲线与其变化特性相同。③房间隔缺损面积在P波顶点、R波顶点、T波起点、T波终点、T-P段时相测值与相对应右心房容积相关性良好,r值分别为0.78、0.75、0.80、0.78、0.77(P均<0.001)。房间隔缺损面积与三尖瓣环运动位移距离呈负相关,r值分别为0.58、0.49、0.52、0.55、0.47(P均<0.05)。④房间隔缺损组心动周期中各时相右心房容积较正常对照组明显增加(P<0.001),三尖瓣环运动位移距离较正常对照组明显减低(P<0.05)。房间隔缺损组右室射血分数低于正常对照组(P<0.05)。第三部分实时三维超声心动图评价正常人右心室整体和局部功能的方法及其准确性研究本研究对36例正常人行三维容积成像,应用四维右心室定量分析法测量右室局部和整体舒张末期容积,收缩末期容积及射血分数,并分别将各局部容积及射血分数行多组间比较。并通过实时三维长轴八平面法和多层螺旋CT法测量右室整体容积及射血分数与上述相关指标行对照分析。以期评价正常人右心室整体和局部容积与功能,并验证这种方法的准确性。结果显示:①四维右心室定量分析法与实时三维长轴八平面法测量的右室整体舒张、收缩末期容积及整体射血分数差异无统计学意义,且相关良好,r值分别为0.96、0.93及0.81。②四维右心室定量分析法与多层螺旋CT法法测量的右室整体舒张、收缩末期容积及整体射血分数差异亦无统计学意义,且相关良好,r值分别为0.96、0.93及0.85。③局部舒张、收缩末期容积测值从右室流入道部、心尖小梁部到流出道部呈递减趋势。心尖小梁部射血分数低于右室流出道部及流入道部测值,差异均有统计学意义(p<0.05);右室整体射血分数与心尖小梁部射血分数差异无统计学意义(p>0.05)。第四部分实时三维超声心动图评价房间隔缺损患者右室整体及局部容积:与正常人对照研究本研究对32例房间隔缺损患者及32例正常对照者行实时三维容积成像,应用四维右室定量分析法测量并比较两组受试者右室局部容积指标和整体舒张、收缩末期容积及相应的局部、整体射血分数。并将实时三维长轴八平面法与四维右室定量分析法测量的整体右室容积及射血分数行相关分析。旨在评价房间隔缺损患者右室整体及局部容积与功能,并比较上述各指标与正常对照组之差异。结果显示:①房间隔缺损患者心尖小梁部射血分数明显低于右室流出道部、流入道部及整体射血分数测值,差异有统计学意义(p<0.05)。②四维右室定量分析法与实时三维长轴八平面法测量的两组受试者整体右室舒张、收缩末期容积及射血分数差异无统计学意义(P>0.05),且相关良好,房间隔缺损组r值分别为0.96、0.92及0.78,对照组r值分别为0.98、0.96及0.87。③房间隔缺损患者右室局部及整体舒张、收缩末期容积较正常对照组明显增加(P<0.05),心尖小梁部及整体射血分数较正常对照组减低(P<0.001),右室流出道部、流入道部射血分数与正常对照组比较差异无统计学意义(P>0.05)。结论1实时三维超声心动图可无创评价心脏空间结构参数的动态变化。正常人房间隔面积的变化特性与右心房容积变化特性和三尖瓣环运动曲线变化趋势相同。2房间隔面积的变化与右心房容积变化及三尖瓣环运动位移距离的变化有关。3房间隔缺损面积在心动周期中呈明显动态变化,具有一定的规律特征。其动态变化曲线与右心房容积动态特性和三尖瓣环运动曲线的变化趋势相同。4房间隔缺损面积动态变化特征的发生机制与右心房压力容积的变化和三尖瓣环的位移变化有关。5房间隔缺损时右心房容量负荷较正常人增加,三尖瓣环运动位移距离减低,右心收缩功能受损。6实时三维超声心动图可准确评价右室整体及局部容积与功能,正常人右室局部收缩功能之间存在差异,这种差异与右心室形态结构和功能有关。7房间隔缺损患者右室各局部收缩功能之间存在差异,整体收缩功能的变化不能代表局部功能的改变。8房间隔缺损患者右室局部及整体容量负荷较正常人显著增加,右室心尖部和整体收缩功能均有降低。右室局部泵功能可早期反映右心功能损害。更多还原

【Abstract】 BACKGROUND AND PURPOSE The clinic importance of atrial septal defect (ASD) consist that it is the common cardiac defects of congenital cardiovascular malformation, accounting for 25%-30% of all congenital heart diseases. Real time three dimensional echocardiography (RT 3DE) developments by Duke University has recently been applied in clinical settings. This technique can analyze the 3D geometry and dynamics of the interatrial septum, display the surrounding relationship of ASD on multi-view image, with meticulous measurements of the size and area of defect, which has an important significance about quantization the ASD size, understanding the relationship between cardiac structure and hemodynamics and selection the suitable management.A study of us assessment the dynamic changes of ASD area by RT 3DE which found the ASD area changed significantly during cardiac cycle. ASD area decreased gradually during atrial contraction and the minimum area was reached at end-diastole, then increased gradually during ventricular contraction and the maximum area was reached at end-systole. The dynamic changes of ASD area were related with the changes of atrial pressure and volume and the translation of the atrioventricular valve ring. The advance in RT 3DE may potentially to study the volume of atrial and the translation of the atrioventricular valve ring which may contribute to the mechanism of ASD area. To explain the changes of atrial volume and the translation of the atrioventricular annulus using 3D view may be improved understanding of the relationship between the changes of cardiac structure and hemodynamics. On the basis of elucidate the mechanism of ASD area change which can enhance to know the status of cardiac contraction and relaxation, the relationship between the load of heart and the degree of disease, which may be helpful to selection suitable management in clinic protocols.The left atrium pressure is higher than right atrium with thinner right ventricular wall and better compliance which result in massive left to right shunt in ASD patient. Long term shunt leads to the development of right heart volume overload and affect right ventricular (RV) function to some extent. The accurate evaluation of RV function has a very important clinic application in assessing the disease condition, choosing therapeutic protocol and monitoring therapeutic efficacy and prognosis of ASD patients. Assessment of RV function in ventriculography, radionuclide imaging, cardiac magnetic resonance imaging, or computed axial tomography may not be feasible and practical because of some limitations. Ultrasonography is the most common method to assess cardiac function with its noninvasive, simple and convenient.However, right ventricle has an irregular shape, with a separate infundibulum and prominent trabecular muscles. It’s difficult to describe the right ventricle by a simple geometric figure and therefore, difficult to assess its function in a conventional two-dimensional echocardiography. Dynamic three-dimensional echocardiography can evaluate RV volume and function but not extensive application because of its time consume and energy to deal with image.Little is known about the tripartite right ventricular modeling in response to volume overload, such as in ASD, because of the complex RV geometry. Moreover, regional RV volume or function can contribute to global regional RV volume or function and reflect regional disorder of myocardium. Tissue Doppler imaging, strain rate imaging, acoustic quantification and velocity vector imaging is the ultrasound technique for analysis of regional RV systolic function from measure regional myocardium translation and systolic velocity and evaluate regional RV pumping function rarely. RT 3DE overcome limited of ultrasound techniques which mentioned above. It obtained RV volume image quickly and combined with three-dimensional workstation to track endocardium that make a live RV three-dimensional image independent of geometric assumption. There are tripartite with right ventricle from the characteristic of morphology and function. The changes of regional RV volume provide information about regional RV pumping function. This study included four parts as follow:Part 1 Evaluation of interatrial septum dynamics and correlation factor in normal human by real time three-dimensional echocardiographyThe purpose of this part was to investigate dynamic changes of interatrial septum (IAS) and its correlation factor. RT 3DE was performed in normal human using a three-dimensional workstation to obtain the en face view of IAS and measure its area at the peak of P-wave, the peak of R-wave, the initial and the destination point of T-wave, and the period of P-T. Measure right atrial volumes in different time which mentioned above and tricuspid annulus motion (TAM) distance in different correspond time period mentioned above, and have correlation analysis with IAS area. RESULTS①The IAS area changed significantly during cardiac cycle,which reached a maximum at end-systole and a minimum at end-diastole. The percentage change ranged from 32.3% to 55.8%, with a mean of 50.7%.②Right atrial volume and the curve of TAM were dynamic changed in cardiac cycle, and the IAS dynamic feature was similar to them.③IAS area has a good correlation with right atrial volume in different time which mentioned above (r=0.78-0.91). IAS area change has a good correlation with TAM distance (r=0.60-0.73).Part 2 Investigation of atrial septal defect area dynamic mechanism by real time three-dimensional echocardiographyThe purpose of this part was to investigate dynamic changes of right atrial volumes and tricuspid annulus motion (TAM) to determinate the mechanism of ASD area dynamic change. RT 3DE was performed in ASD patients and control group using a three-dimensional workstation to measure defect area and IAS area at the peak of P-wave, the peak of R-wave, the initial and the destination point of T-wave, and the period of P-T. Measure right atrial volumes in different time which mentioned above and TAM distance in different correspond time period mentioned above, and have correlation analysis with ASD area. A comparison results including right atrial volumes, TAM distance and RV function between ASD and control group. RESULTS①The ASD area changed significantly during cardiac cycle,ASD area decreased gradually with atrial contraction and the minimum area was reached at end-diastole that with the change curve reached the lowest point, then increased gradually during ventricular contraction and the maximum area was reached at end-systole that with the change curve reached the highest peak. The percentage change ranged from 40.4% to 77.2%, with a mean of 60.3%.②Right atrial volume and the curve of TAM were dynamic changed in cardiac cycle, and the ASD area dynamic feature was similar to them.③ASD area has a good correlation with right atrial volume in different time which mentioned above (r=0.75-0.80 P<0.001). ASD area change has a negative correlation with TAM distance (r=0.47-0.58, P<0.05).④Right atrial volume in different time of cardiac cycle was higher than result of control group (P<0.001). TAM distance and RV ejection fraction was lower than result of control group (P<0.05).Part 3 Assessment of normal global and regional right ventricular function by real-time three-dimensional echocardiography and its accuracy evaluationThe purpose of this part was to investigate global and regional RV volume or function and verify its accuracy. RT-3DE was performed in 36 healthy individuals. Regional and global right ventricular end-diastolic volume, end-systolic volume and ejection fraction were measured by 4D right ventricular quantitation (4D RVQ) method. The regional parameters in different right ventricular components were compared respectively. The global parameters derived from 4D RVQ were compared with the results of longitudinal Axial 8 plane (LA 8-plane) and Multi-Slice Computed Tomography (MSCT) measurements. RESULTS①Global RV end-diastolic volume, end-systolic volume and ejection fraction obtained from 4D RVQ method was no statistic significance and correlated significantly with LA 8-plane findings (r=0.96, 0.93 and 0.81 respectively).②Global right ventricular end-diastolic volume, end-systolic volume and ejection fraction obtained from 4D RVQ method was no statistic significance and correlated significantly with MSCT findings (r=0.96, 0.93 and 0.85 respectively).③Regional volume is decrease progressively from inlet portion, apical trabecular portion to outlet portion. Regional right ventricular ejection fraction is lower in the apical trabecular portion than the inlet (p<0.05) and outlet portion (p<0.05). Apical trabecular portion ejection fraction was no statistic significance with global measurement (p>0.05).Part 4 Assessment of global and regional right ventricular function in atrial septal defect patients by real time three-dimensional echocardiography: A control studyThe purpose of this part was to study global and regional RV volume or function in ASD patients and compare with normal subjects. RT 3DE were performed in 32 ASD patients (ASD group) and 32 healthy individuals (control group). Some parameters were measured by 4D RVQ method and compared with the two groups. The index include global RV end-diastole or systole volume, regional RV end-diastole or systole volume including inlet, apical trabecular and outlet portions, global RV ejection fraction and regional RV ejection fraction including tripartite which mentions above. The global parameters derived from 4D RVQ were compared with LA 8-plane measurements. RESULTS①Regional RV ejection fraction is lower in the apical trabecular portion than the inlet, outlet portion and global RV ejection fraction (p<0.05).②Global RV end-diastolic volume, end-systolic volume and ejection fraction obtained from 4D RVQ method were no statistic significance and have an excellent correlation with LA 8-plane findings, r=0.96, 0.92 and 0.78 (ASD group),r=0.98, 0.96 and 0.87 (control group).③Global and regional RV end diastolic or systolic volume of ASD patients was higher and apical trabecular portion, global RV ejection fraction was lower than control group (P<0.001). Inlet portion, outlet portion RV ejection fraction was no statistical significant as compared with controls (P>0.05).CONCLUSIONS1 Real time three-dimensional echocardiography can assess dynamic changes of parameters of cardiac spatial structure noninvasive. Interatrial septum dynamic feature was similar to the dynamic curve of right atrial volume and tricuspid annulus during cardiac cycle in normal individual.2 Interatrial septum area was related with the change of right atrial volume and tricuspid annulus motion.3 The ASD area changed significantly and regularity during cardiac cycle. The curve of ASD area was similar to dynamic change of right atrial volume and curve of tricuspid annulus motion.4 The ASD area was related with the change of right atrial volume and tricuspid annulus motion. 5 ASD leads to right atrial volume overload, tricuspid annulus motion decreased and right ventricular dysfunction.6 RT3DE can evaluate global and regional right ventricular volume and function accurately, and the systolic function is difference to each portion of right ventricular in normal which may be related to morphology and function of right ventricular.7 The systolic function is difference to each portion of right ventricular in ASD patients and the global right ventricular function is not represented the change of regional right ventricular function.8 Global and regional right ventricular volume was increased and apical trabecular portion, global right ventricular ejection fraction was decreased in ASD patients. Regional right ventricular pumping function might reflect right ventricular dysfunction.更多还原