Department of Electrical and Computer Engineering, The University of Iowa, Iowa City, IA 52242, USA.
IEEE Trans Med Imaging. 2013 Feb;32(2):376-86. doi: 10.1109/TMI.2012.2227120. Epub 2012 Nov 15.
Segmentation of multiple surfaces in medical images is a challenging problem, further complicated by the frequent presence of weak boundary evidence, large object deformations, and mutual influence between adjacent objects. This paper reports a novel approach to multi-object segmentation that incorporates both shape and context prior knowledge in a 3-D graph-theoretic framework to help overcome the stated challenges. We employ an arc-based graph representation to incorporate a wide spectrum of prior information through pair-wise energy terms. In particular, a shape-prior term is used to penalize local shape changes and a context-prior term is used to penalize local surface-distance changes from a model of the expected shape and surface distances, respectively. The globally optimal solution for multiple surfaces is obtained by computing a maximum flow in a low-order polynomial time. The proposed method was validated on intraretinal layer segmentation of optical coherence tomography images and demonstrated statistically significant improvement of segmentation accuracy compared to our earlier graph-search method that was not utilizing shape and context priors. The mean unsigned surface positioning errors obtained by the conventional graph-search approach (6.30 ±1.58 μ m) was improved to 5.14±0.99 μ m when employing our new method with shape and context priors.
医学图像中多个表面的分割是一个具有挑战性的问题,由于边界证据较弱、物体变形大以及相邻物体之间的相互影响等因素,使得问题更加复杂。本文提出了一种新的多目标分割方法,该方法在三维图论框架中结合了形状和上下文先验知识,以帮助克服上述挑战。我们采用基于弧的图表示法,通过成对的能量项来整合广泛的先验信息。具体来说,使用形状先验项来惩罚局部形状变化,使用上下文先验项来惩罚局部表面距离相对于期望形状和表面距离模型的变化。通过计算低阶多项式时间内的最大流来获得多个表面的全局最优解。该方法在光学相干断层扫描图像的视网膜内部分层中进行了验证,与我们之前未利用形状和上下文先验的图搜索方法相比,分割准确性有了显著提高。在使用我们的新方法结合形状和上下文先验时,传统的图搜索方法(6.30±1.58μm)得到的平均无符号表面定位误差提高到了 5.14±0.99μm。