Lee-Han H, Cooke G, Boyd N F
Division of Epidemiology and Biostatistics, Ontario Cancer Institute, Toronto, Canada.
Eur J Cancer Prev. 1995 Aug;4(4):285-92. doi: 10.1097/00008469-199508000-00003.
Differences in the proportion of the breast occupied by mammographic densities have been shown to be associated with differences in breast cancer risk. However, estimation of these densities by radiologists may be subject to error, and it is likely that quantitative measurement will reduce misclassification of densities and strengthen their association with risk of breast cancer. The objective of this study was to compare the extent of mammographic densities estimated subjectively by an experienced radiologist with the measured extent of densities using a digital planimeter. A total of 225 sets of mammograms from women aged 40-49 years and enrolled in the Canadian National Breast Screening Study (NBSS) were selected. The extent of the radiological densities was estimated visually by one radiologist. Independently, the total area of the breast and the areas of density were traced and measured using a digital planimeter. Visual estimations and measurements of mammographic densities were then compared to determine the extent of agreement between the two methods. In general, the two methods showed good agreement (kappa = 0.78). The measured area of mammographic densities tended to be slightly greater than the radiologist's estimations. Both methods were highly reproducible (radiologist-dependent method, kappa = 0.89; quantitative method, r = 0.95, P = 0.0001). Our results indicate that measurement of the area of mammographic density using a quantitative method is reliable, and correlates well with assessment by an experienced radiologist. The method may be useful for identifying women at increased risk of breast cancer.
乳房X线摄影密度所占据乳房的比例差异已被证明与乳腺癌风险差异相关。然而，放射科医生对这些密度的估计可能会出现误差，而定量测量可能会减少密度的错误分类，并加强它们与乳腺癌风险的关联。本研究的目的是比较一位经验丰富的放射科医生主观估计的乳房X线摄影密度范围与使用数字面积测量仪测量的密度范围。总共选择了225例年龄在40 - 49岁、参加加拿大国家乳腺筛查研究（NBSS）的女性的乳房X线照片。由一位放射科医生目测估计放射学密度的范围。独立地，使用数字面积测量仪描绘并测量乳房的总面积和密度区域。然后比较乳房X线摄影密度的目测估计值和测量值，以确定两种方法之间的一致程度。总体而言，两种方法显示出良好的一致性（kappa = 0.78）。乳房X线摄影密度的测量面积往往略大于放射科医生的估计值。两种方法都具有高度的可重复性（依赖放射科医生的方法，kappa = 0.89；定量方法，r = 0.95，P = 0.0001）。我们的结果表明，使用定量方法测量乳房X线摄影密度面积是可靠的，并且与经验丰富的放射科医生的评估相关性良好。该方法可能有助于识别乳腺癌风险增加的女性。
