H. Lee Moffitt Cancer Center & Research Institute, Cancer Prevention & Control Division, Tampa, FL 33612, USA.
Acad Radiol. 2011 May;18(5):547-55. doi: 10.1016/j.acra.2010.12.007. Epub 2011 Mar 2.
Breast density is a significant breast cancer risk factor measured from mammograms. Evidence suggests that the spatial variation in mammograms may also be associated with risk. We investigated the variation in calibrated mammograms as a breast cancer risk factor and explored its relationship with other measures of breast density using full field digital mammography (FFDM).
A matched case-control analysis was used to assess a spatial variation breast density measure in calibrated FFDM images, normalized for the image acquisition technique variation. Three measures of breast density were compared between cases and controls: (a) the calibrated average measure, (b) the calibrated variation measure, and (c) the standard percentage of breast density (PD) measure derived from operator-assisted labeling. Linear correlation and statistical relationships between these three breast density measures were also investigated.
Risk estimates associated with the lowest to highest quartiles for the calibrated variation measure were greater in magnitude (odds ratios: 1.0 [ref.], 3.5, 6.3, and 11.3) than the corresponding risk estimates for quartiles of the standard PD measure (odds ratios: 1.0 [ref.], 2.3, 5.6, and 6.5) and the calibrated average measure (odds ratios: 1.0 [ref.], 2.4, 2.3, and 4.4). The three breast density measures were highly correlated, showed an inverse relationship with breast area, and related by a mixed distribution relationship.
The three measures of breast density capture different attributes of the same data field. These preliminary findings indicate the variation measure is a viable automated method for assessing breast density. Insights gained by this work may be used to develop a standard for measuring breast density.
乳腺密度是通过乳房 X 光照片测量的一个重要乳腺癌风险因素。有证据表明，乳房 X 光照片的空间变化也可能与风险相关。我们研究了校准乳房 X 光照片的变化作为乳腺癌风险因素，并使用全视野数字乳房 X 光摄影（FFDM）探索了其与其他乳腺密度测量方法的关系。
采用病例对照匹配分析来评估校准 FFDM 图像中空间变化乳腺密度测量值，该值针对图像采集技术变化进行了归一化。在病例和对照组之间比较了三种乳腺密度测量值：（a）校准平均测量值，（b）校准变化测量值，以及（c）源自操作员辅助标记的标准百分比乳腺密度（PD）测量值。还研究了这三种乳腺密度测量值之间的线性相关性和统计学关系。
与校准变化测量值的最低至最高四分位数相关的风险估计值的幅度更大（比值比：1.0 [参考]，3.5，6.3 和 11.3），而与标准 PD 测量值四分位数的相应风险估计值（比值比：1.0 [参考]，2.3，5.6 和 6.5）和校准平均测量值（比值比：1.0 [参考]，2.4，2.3 和 4.4）相比。这三种乳腺密度测量值高度相关，与乳房面积呈反比关系，并且通过混合分布关系相关。
三种乳腺密度测量值均捕获了同一数据字段的不同属性。这些初步发现表明，变化测量值是评估乳腺密度的一种可行的自动化方法。通过这项工作获得的见解可用于开发测量乳腺密度的标准。
