From Point to Local Neighborhood: Polyp Detection in CT Colonography Using Geodesic Ring Neighborhoods
From Point to Local Neighborhood: Polyp Detection in CT Colonography Using Geodesic Ring Neighborhoods
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DOI：
10.1109/tip.2010.2076295
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发表时间：
2011-04
影响因子：
10.6
通讯作者：
J. Ong;A. Seghouane
中科院分区：
文献类型：
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作者：
J. Ong;A. Seghouane
现有的息肉检测方法严重依赖于基于曲率的特征来区分病变。这些假设离散三角曲面网格或体积非常接近光滑的连续曲面。然而，通常情况并非如此，因为曲率是作为局部特征和二阶微分量计算的，噪声的存在会显著影响其估计。出于这个原因，需要一个更全局的特征来提供对手头表面的准确描述。本文提出了一种利用表面斑块质心周围的局部邻域进行图像提取的新方法。这是使用测地线环来完成的，测地线环在这个质心周围的一个邻域积累曲率信息。这个测地线环邻域近似于一个光滑的连续表面，曲率和方向估计方法可以在其上应用。引入并计算了一种新的全局形状指数S。这些曲率和方向值将用于将表面分类为球根状息肉、脊状褶皱或半平面结构。实验结果表明，该方法在区分结肠的球根性息肉、褶皱和平面样结构方面具有良好的前景（100%的灵敏度，100%的特异性，病灶为>;10 mm）。
Existing polyp detection methods rely heavily on curvature-based characteristics to differentiate between lesions. These assume that the discrete triangulated surface mesh or volume closely approximates a smooth continuous surface. However, this is often not the case and because curvature is computed as a local feature and a second-order differential quantity, the presence of noise significantly affects its estimation. For this reason, a more global feature is required to provide an accurate description of the surface at hand. In this paper, a novel method incorporating a local neighborhood around the centroid of a surface patch is proposed. This is done using geodesic rings which accumulate curvature information in a neighborhood around this centroid. This geodesic-ring neighborhood approximates a single smooth, continuous surface upon which curvature and orientation estimation methods can be applied. A new global shape index, S is also introduced and computed. These curvature and orientation values will be used to classify the surface as either a bulbous polyp, ridge-like fold or semiplanar structure. Experimental results show that this method is promising (100% sensitivity, 100% specificity for lesions >;10 mm) for distinguishing between bulbous polyps, folds and planar-like structures in the colon.