【作者】 刘奇；

【导师】 郑昌琼；

【作者基本信息】 四川大学 ， 生物医学工程， 2004， 博士

【摘要】 二尖瓣病变是心脏疾病的常见病变,根据报道二尖瓣病变占风心病的85%,如二尖瓣关闭不全将导致反流出现,因此研究二尖瓣反流有十分重要的意义。在二十世纪八十年代,彩色多普勒血流技术成为了医生诊断二尖瓣反流最重要的工具,与别的方法相比,该技术操作方便、无副作用、成本低,因此很快成为诊断复杂二尖瓣反流和定量分析的研究方法。通过经食道超声心动图(TEE)和经胸超声心动图(TTE)可以判定二尖瓣反流机制、检出反流起源部位、评价反流程度及术后判定残余反流量,但无法准确测量反流量,不能对二尖瓣反流进行真实、客观有效的评价,对于复杂的二尖瓣偏心反流常会被严重低估,无法准确观察和测量,只能靠主观推断,存在较大的误差。此外,在临床上对心脏二尖瓣反流的测量没有金标准,因此,急需研究新的真实、客观有效的观察和定量评价方法。本论文在二维彩色多普勒血流图像基础上,利用超声图像三维重建方法,实现三维彩色多普勒超声心动图对二尖瓣反流速度的空间分布描述,可以立体观察反流的有无、位置、方向、反流束长度、面积、体积、空间传播和严重程度,可以对复杂的二尖瓣偏心反流进行较为准确的半定量评价,通过计算反流体积可以区分传统方法无法识别的反流级别,显示了定量评价二尖瓣偏心反流在临床上的应用潜力。首先,利用经胸超声心动图获取原始的二尖瓣中心反流图像,根据超声图像中Speckle噪声的特点,选择了数学形态学滤波器来进行滤波,该方法可以有效滤除超声图像中的Speckle噪声并同时保留细节信息。从滤波后的图像中提取<WP=4>出感兴趣区域后,将其在空间按原始图像获取角度重新组织,并利用三维直接匹配插值算法得到规则体数据,体绘制方法得到的结果有助于临床评价二尖瓣反流的严重程度,尤其是立体观察和确定反流束的位置、方向、长度、宽度、面积、流程、起止点和严重程度以及空间分布状态等,在医学上具有重要的价值。然后,利用多平面经食管的方法获取心脏的原始超声多普勒图像,并同步记录心电图。再经过滤波、插值实现了面绘制和体绘制两种体视化方法。通过对多普勒超声医学图像中图像叠加原理和Color Bar的分析,从多普勒血流图中分离出血流运动的速度信息和解剖结构信息,分别进行三维重建,并将重建结果进行三维融合显像,从而显示血流在心腔内的运动情况以及反流的有无、位置、时相、方向、反流束长度、面积等,得到了反流在不同角度的面积和体积变化趋势以及反流在不同时相的变化趋势,在不同的收缩期时相和不同的旋转角度的条件下,三维重建呈现的偏心性反流束均明显大于二维彩色多普勒所显示的偏心性反流束,可更准确地显示二尖瓣偏心性反流束的大小。最后,将实时三维超声图像与彩色多普勒相结合,重建立体的彩色血流图像,立体显示反流束的位置、时相、方向、长度、宽度、面积、体积、流程和严重程度,对反流进行了比较精确的定量。该方法在目前的文献中未见报道。本研究表明,彩色多普勒血流图像的三维重建方法与传统方法相比能够更准确评价二尖瓣偏心反流程度,对二尖瓣病变的正确诊断和有效治疗具有临床意义,在社会上具有实际应用价值。更多还原

【Abstract】 Mitral valve disease is one of the frequent diseases of heart disease; the recent statistical reports proved that mitral valve pathological change take 85 percent of heart rheumatism. Mitral valve insufficiency causes the mitral regurgitation, so it has important signification that research the mitral valve regurgitation.In the eighties of the twentieth century the color Doppler flow imaging technology come forth, color Doppler flow imaging is the most important tools for doctor to diagnosis the mitral regurgitation. Compare with other tools, it’s facility, no side-effect and cheap. It also has shortages such as heavy speckle noise and low resolution. So it becomes the most important fields that diagnosis the complex mitral regurgitation and quantitative analysis from the color Doppler flow images.Transthoracic Echocardiography and Transesophageal Echocardiography (TTE and TEE) plays an important role in the assessment of the mitral regurgitation mechanism, origin position, regurgitation severity level and residual regurgitation amount after surgical operation, however, it’s difficult to exactly observe and measure the regurgitation from the two-dimensional real-time echocardiograph. It’s difficult to give the objective assessment of the mitral regurgitation,especially for <WP=6>the eccentric regurgitation and there is subjective assertion, underestimation and wider error band from the two-dimensional Doppler echocardiograph; Moreover, there is no golden standard of the clinic mitral regurgitation measurement; it’s needed to develop true objective observing and new quantitative assessment method. Based on the two-dimensional color Doppler image and the three-dimensional rconstruction method in this article, the technique of three-dimensional reconstruction and the color Doppler flow image is combined to implement the description of the mitral regurgitation velocity space distribution, which can be used in observing the position, direction and measuring the jet length, area, volume, space distribution and severity level of the mitral regurgitation, especially more accurate semi-quantitative assessment of the complex mitral eccentric regurgitation, compared to the traditional method, by calculating the volume of the mitral regurgitation, the regurgitation severity level specification could be given. The accurate assessment of mitral eccentric regurgitation is of great clinic significance. First, TTE method is used to acquire original mitral centric regurgitation echocardiography. According to the characteristic of speckle noise in ultrasound images, mathmitical morphological filter is used to suppress speckle and preserve the details in these images. Then the images are reorganized according to their corresponsive acquisition angle after the extraction of region of interest. A direct matching interpolation method is utilized to get regular volume data from discrete distribution of ultrasound information points. This volume data can be visualized with surface rendering and volume rendering algorithm, which can be used in observing the position, direction and measuring the jet length, area, volume, space distribution and severity level of the mitral regurgitation, the experiment result is of of great clinic significance.Then, Multiplane transesophageal rotational scanning method is used to acquire original Doppler echocardiography while echocardiogram is recorded synchronously. After filtering and interpolation, the surface rendering and volume rendering methods are performed. Through analyzing the color-bar information and the color Doppler flow image’s superposition principle, the grayscale mitral anatomical structure and <WP=7>color-coded regurgitation velocity parameter were seperated from color Doppler flow images, three-dimensional reconstruction of mitral structure and regurgitation velocity distribution was implemented separately, fusion visualization of the reconstructed regurgitation velocity distribution parameter with its corresponding 3D mitral anatomical structures was realized, whi更多还原