An Anatomically Oriented Breast Coordinate System for Mammogram Analysis
An Anatomically Oriented Breast Coordinate System for Mammogram Analysis
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DOI：
10.1109/tmi.2011.2155082
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发表时间：
2011-10-01
影响因子：
10.6
通讯作者：
Nielsen, Mads
中科院分区：
文献类型：
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作者：
Brandt, Sami S.;Karemore, Gopal;Nielsen, Mads
我们开发了一种基于乳房解剖学的乳房坐标系统，将女性乳房注册到二维中外侧（ML）或中外侧斜位（MLO）乳房x光片的共同坐标框架中。乳房是根据胸肌和乳头的位置以及乳房边界的形状进行登记的，因为这些是最强大的特征，与乳房的大小和形状无关。在这些标志的基础上，我们在乳房x光片的参数框架和乳房区域之间构建了一个非线性映射。这种映射使得在所有ML或MLO乳房x线照片中识别相应的位置和方向成为可能，这有利于隐式使用配准，也就是说，不需要显式的图像扭曲。我们还展示了如何使用坐标变换来提取高斯导数特征，以便在不非线性变形图像的情况下注册和提取特征位置和方向。我们在对490名妇女进行的横断面乳腺癌风险评估研究中使用了拟议的乳房坐标变换，在这项研究中，我们试图从乳房x光片中了解乳腺癌的风险因素，这些x光片是在放射科医生可以看到乳腺癌之前拍摄的。坐标系统提供了乳房区域的相对位置和方向信息，这些特征是从乳房区域派生出来的。此外，该坐标系统可用于时间研究，以确定每个妇女的乳房x光片与研究中所有妇女的乳房x光片之间的解剖等效位置。横断面研究的结果表明，与其他评估系统相比，使用新的坐标系统可以改进对癌症和对照组的分类。采用受者工作特征曲线下面积评分进行比较。总的来说，新的坐标系统使乳房的精确解剖注册成为可能，这表明它在任何需要二维乳房x线照片注册的地方都具有广泛的适用性。
We have developed a breast coordinate system that is based on breast anatomy to register female breasts into a common coordinate frame in 2-D mediolateral (ML) or mediolateral oblique (MLO) view mammograms. The breasts are registered according to the location of the pectoral muscle and the nipple and the shape of the breast boundary because these are the most robust features independent of the breast size and shape. On the basis of these landmarks, we have constructed a nonlinear mapping between the parameter frame and the breast region in the mammogram. This mapping makes it possible to identify the corresponding positions and orientations among all of the ML or MLO mammograms, which facilitates an implicit use of the registration, i.e., no explicit image warping is needed. We additionally show how the coordinate transform can be used to extract Gaussian derivative features so that the feature positions and orientations are registered and extracted without nonlinearly deforming the images. We use the proposed breast coordinate transform in a cross-sectional breast cancer risk assessment study of 490 women, in which we attempt to learn breast cancer risk factors from mammograms that were taken prior to when the breast cancer became visible to a radiologist. The coordinate system provides both the relative position and orientation information on the breast region from which the features are derived. In addition, the coordinate system can be used in temporal studies to pinpoint anatomically equivalent locations between the mammograms of each woman and among the mammograms of all of the women in the study. The results of the cross-sectional study show that the classification into cancer and control groups can be improved by using the new coordinate system, compared to other systems evaluated. Comparisons were performed using the area-under-the-receiver-operating-characteristic-curve score. In general, the new coordinate system makes an accurate anatomical registration of breasts possible, which suggests its wide applicability wherever 2-D mammogram registration is required.