基于ASM水平集分割方法的心脏同步功能估计

      Cardiac Synchronization Function Estimation Based on ASM Level Set Segmentation Method

      • 摘要: 目前在测定心脏机械同步性方面尚无精确定量的无创手段,而利用医学影像定量测定心脏四腔的同步性有较大的临床意义。该文以全心脏超声序列图像为基础,将每一帧图像的左右心房和左右心室进行分割,记录下每一帧图像分割得到的各腔包含的像素点个数,得到四腔的面积随时间的变化曲线。然后从四腔的面积变化曲线进行特征提取,得到心脏四腔的同步性信息。由于超声图像信噪较低,四腔轮廓线与背景难以区分,因此心脏四腔轮廓线的提取是一个具有挑战性的问题。为此,ASM形状模型的信息被加入到了传统的水平集方法中,用于催动曲线的演化过程,并约束曲线的形状。根据改进的水平集方法用于真实超声数据的实验结果,可以看出改进方法得到准确的效果。然后以左右心室的分割结果为基础,根据面积变化,对于左右心室的收缩功能进行了评价。进一步根据分割结果,通过面积变化曲线以及容积变化曲线进行分析,对于心脏四腔室的同步性进行了估计。

         

        Abstract: At present, there is no accurate and quantitative method for the determination of cardiac mechanical synchronism, and quantitative determination of the synchronization function of the four cardiac cavities with medical images has great clinical value. This paper uses the whole heart ultrasound image sequence, and segments the left & right atriums and left & right ventricles of each frame. After the segmentation, the number of pixels in each cavity and in each frame is recorded, and the areas of the four cavities of the image sequence are therefore obtained. The area change curves of the four cavities are further extracted, and the synchronous information of the four cavities is obtained. Because of the low SNR of Ultrasound images, the boundary lines of cardiac cavities are vague, so the extraction of cardiac contours is still a challenging problem. Therefore, the ASM model information is added to the traditional level set method to force the curve evolution process. According to the experimental results, the improved method improves the accuracy of the segmentation. Furthermore, based on the ventricular segmentation, the right and left ventricular systolic functions are evaluated, mainly according to the area changes. The synchronization of the four cavities of the heart is estimated based on the area changes and the volume changes.

         

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