Segmentation of the left ventricle in ultrasound images for viewing through different axes is a critical aspect. This paper proposes the development of novel active contour models with shape constraint to segment the left ventricle in three different axis views of the ultrasound images. The shapes observed in all the axis views of the left ventricle were not similar. According to the cardiac cycle, the valve opening in the end-diastolic phase influenced the left ventricle segmentation; hence, a shape constraint was embedded in the active contour model to keep ventricle’s shape, especially in the Apical long-axis view and Apical four-chamber view. Furthermore, for different axes views, diverse active contour models were proposed to fit each situation. The shape constraint in each function for different views exhibited a specific shape during the function iteration. In order to speed up the algorithm evolution, previous results were used for the initialization of the present active contour. We evaluated the proposed method on 57 patients with three different views: Apical long-axis view, Apical four-chamber view and Short-axis view at the papillary muscle level and obtained the Dice similarity coefficients of 0.86±0.05, 0.90±0.06 and 0.90±0.06 and the Hausdorff distance metrics of 10.11±4.66, 7.41±4.46 and 9.98±6.58, respectively. The qualitative and quantitative evaluations showed an advantage of our method in terms of segmentation accuracy.

中文翻译：

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基于主动轮廓模型的左心室在超声图像中的不同轴视图分割

在超声图像中分割左心室以便通过不同轴进行观察是一个关键方面。本文提出开发具有形状约束的新型主动轮廓模型，以在超声图像的三个不同轴视图中分割左心室。在左心室的所有轴视图中观察到的形状并不相似。根据心动周期，舒张末期瓣膜开度影响左心室分割；因此，在活动轮廓模型中嵌入了形状约束以保持心室的形状，特别是在心尖长轴视图和心尖四腔视图中。此外，对于不同的轴视图，提出了不同的活动轮廓模型以适应每种情况。不同视图的每个函数中的形状约束在函数迭代期间表现出特定的形状。为了加快算法的演进，之前的结果被用于当前活动轮廓的初始化。我们对 57 名具有三种不同视图的患者评估了所提出的方法：心尖长轴视图、心尖四腔视图和乳头肌水平的短轴视图，并获得了 Dice 相似系数0.86±0.05,0.90±0.06和0.90±0.06和 Hausdorff 距离度量10.11±4.66,7.41±4.46和9.98±6.58， 分别。定性和定量评估显示了我们的方法在分割准确性方面的优势。