Structure-analysis method for electronic cleansing in cathartic and noncathartic CT colonography
Structure-analysis method for electronic cleansing in cathartic and noncathartic CT colonography
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DOI：
10.1118/1.2936413
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发表时间：
2008-07-01
期刊：
影响因子：
3.8
通讯作者：
Yoshida, Hiroyuki
中科院分区：
文献类型：
--
作者：
Cai, Wenli;Zalis, Michael E.;Yoshida, Hiroyuki
电子清洗（EC）是一种用于CT结肠成像（CTC）中粪便物质分割的新兴方法，用于减少或消除对泻药肠道准备的要求，从而提高患者对结肠癌筛查建议的依从性。在EC中，由X射线不透明的口服造影剂标记的粪便从CTC图像中去除，在图像采集后有效地清洁结肠。现有的EC方法倾向于遭受以下清洁伪影：由于周围标记的粪便物质引起的伪增强而导致的软组织结构的退化，以及由在空气腔和标记区域之间的边界（称为空气标记边界（AT边界））处的部分体积效应引起的伪软组织结构和假瘘管。在这项研究中，我们开发了一种新的EC方法，称为结构分析清洗，有效地避免了这些清洗文物。在我们的方法中，淹没的软组织结构被识别的局部形态特征，其特征在于基于一个三维海森矩阵的特征值。一个结构增强功能制定的软组织结构的增强。此外，夹在空气腔和标记区域之间的薄褶皱通过基于多尺度体积曲率的局部粗糙度分析来增强。结构增强函数和局部粗糙度的值都被集成到水平集方法的速度函数中，用于描绘标记的粪便材料。因此，保留了浸没的软组织结构以及附着到标记区域的软组织结构，而标记区域与相关AT边界一起从CTC图像中沿着被去除。基于结肠体模中的息肉和褶皱以及具有液体和粪便标记的临床泻药和非泻药CTC病例中的息肉对清洁质量进行的评估表明，我们的结构分析清洁方法显着优于我们之前基于阈值的EC方法。上级。它提供了一个清洁的结肠，大大减少了减影伪影。(C)2008年美国医学物理学家协会。
Electronic cleansing (EC) is an emerging method for segmentation of fecal material in CT colonography (CTC) that is used for reducing or eliminating the requirement for cathartic bowel preparation and hence for improving patients' adherence to recommendations for colon cancer screening. In EC, feces tagged by an x-ray-opaque oral contrast agent are removed from the CTC images, effectively cleansing the colon after image acquisition. Existing EC approaches tend to suffer from the following cleansing artifacts: degradation of soft-tissue structures because of pseudo-enhancement caused by the surrounding tagged fecal materials, and pseudo soft-tissue structures and false fistulas caused by partial volume effects at the boundary between the air lumen and the tagged regions, called the air-tagging boundary (AT boundary). In this study, we developed a novel EC method, called structure-analysis cleansing, which effectively avoids these cleansing artifacts. In our method, submerged soft-tissue structures are recognized by their local morphologic signatures that are characterized based on the eigenvalues of a three-dimensional Hessian matrix. A structure-enhancement function is formulated for enhancing of the soft-tissue structures. In addition, thin folds sandwiched between the air lumen and tagged regions are enhanced by analysis of the local roughness based on multi-scale volumetric curvedness. Both values of the structure-enhancement function and the local roughness are integrated into the speed function of a level set method for delineating the tagged fecal materials. Thus, submerged soft-tissue structures as well as soft-tissue structures adhering to the tagged regions are preserved, whereas the tagged regions are removed along with the associated AT boundaries from CTC images. Evaluation of the quality of the cleansing based on polyps and folds in a colon phantom, as well as on polyps in clinical cathartic and noncathartic CTC cases with fluid and stool tagging, showed that our structure-analysis cleansing method is significantly superior to that of our previous thresholding-based EC method. It provides a cleansed colon with substantially reduced subtraction artifacts. (C) 2008 American Association of Physicists in Medicine.