Cancer Research Center of Hawaii, 1236 Lauhala St., Honolulu, HI 96813, USA.
Cancer Epidemiol. 2011 Apr;35(2):188-93. doi: 10.1016/j.canep.2010.06.009. Epub 2010 Aug 4.
While use of mammography is limited, due to concerns related to radiation exposure, dual energy X-ray absorptiometry (DXA), commonly available in medical care settings, is characterized by low radiation exposure.
In the current paper, we compared breast density measured by DXA with mammographic density in 101 adult women who had a screening mammogram during the last 2 years. DXA scans of both breasts were taken using a clinical DXA system calibrated to measure breast density. The total projected breast area was manually delineated on each image and percent fibroglandular volume density (%FGV), absolute fibroglandular volume, total breast area and volume were computed. After digitizing mammographic films, total breast area, dense area, and percent density (PD) were estimated using computer-assisted mammographic density assessment.
Both DXA and mammographic measures showed high correlations between left and right breasts ranging from 0.85 to 0.98 (p<0.0001). Mean %FGV was 38.8±14.3%, and mean percent density was 31.9±18.2% for craniocaudal views and 28.3±16.2% for mediolateral views. The correlation between the two measures was 0.76 for both views (p<0.0001). Associations with common risk factors showed similar patterns for DXA and mammographic densities; in particular, the inverse associations with BMI and age at menarche were evident for both methods. Multilinear regression with stepwise selection indicated an explained variance of 0.56 for %FGV alone and of 0.58 for %FGV plus number of children.
Despite some differences in methodology, the current comparison suggests that DXA may provide a low-radiation option in evaluating breast density.
虽然由于与辐射暴露相关的担忧，乳房 X 光摄影的应用受到限制，但双能 X 射线吸收测定法（DXA）在医疗环境中普遍可用，其特点是辐射暴露低。
在当前的论文中，我们比较了在过去 2 年内接受筛查性乳房 X 光摄影的 101 名成年女性中，DXA 测量的乳房密度与乳房 X 光摄影密度。使用经过校准以测量乳房密度的临床 DXA 系统对双侧乳房进行 DXA 扫描。在每个图像上手动描绘总投影乳房区域，并计算纤维腺体体积密度（%FGV）、绝对纤维腺体体积、总乳房面积和体积。在对乳房 X 光片进行数字化后，使用计算机辅助乳房密度评估法估计总乳房面积、致密区域和密度百分比（PD）。
DXA 和乳房 X 光摄影测量值在左右乳房之间均显示出高度相关性，范围从 0.85 到 0.98（p<0.0001）。头足位的平均 %FGV 为 38.8±14.3%，平均密度百分比为 31.9±18.2%；内外侧位为 28.3±16.2%。两种方法的两个测量值之间的相关性为 0.76（p<0.0001）。与常见危险因素的关联显示，DXA 和乳房 X 光摄影密度的模式相似；特别是，与 BMI 和初潮年龄的反比关系在两种方法中均很明显。逐步选择的多元线性回归表明，仅 %FGV 可解释 0.56 的方差，而 %FGV 加儿童数量可解释 0.58 的方差。
尽管方法上存在一些差异，但目前的比较表明，DXA 可能为评估乳房密度提供一种低辐射选择。
