Tu and Yuen Center for Functional Onco-imaging, Irvine, California 92697, USA.
Med Phys. 2010 Jun;37(6):2770-6. doi: 10.1118/1.3426317.
The purpose of this study was to evaluate the age- and race-dependence of the breast fibroglandular tissue density based on three-dimensional breast MRI.
The normal breasts of 321 consecutive patients including Caucasians, Asians, and Hispanics were studied. The subjects were separated into three age groups: Younger than 45, between 45 and 55, and older than 55. Computer algorithms based on body landmarks were used to segment the breast, and fuzzy c-means algorithm was used to segment the fibroglandular tissue. Linear regression analysis was applied to compare mean differences among different age groups and race/ethnicity groups. The obtained parameters were not normally distributed, and the transformed data, natural log (ln) for the fibroglandular tissue volume, and the square root for the percent density were used for statistical analysis.
On the average, the transformed fibroglandular tissue volume and percent density decreased significantly with age. Racial differences in mean transformed percent density were found among women older than 45, but not among women younger than 45. Mean percent density was higher in Asians compared to Caucasians and Hispanics; the difference remained significant after adjustment for age, but not significant after adjusted for both age and breast volume. There was no significant difference in the density between the Caucasians and the Hispanics.
The results analyzed using the MRI-based method show age- and race-dependence, which is consistent with literature using mammography-based methods.
本研究旨在基于三维乳腺 MRI 评估乳腺纤维腺体组织密度的年龄和种族依赖性。
研究纳入了包括白种人、亚洲人和西班牙裔在内的 321 名连续患者的正常乳房。受试者分为三组年龄组：<45 岁、45-55 岁和>55 岁。基于身体标志的计算机算法用于分割乳房，模糊 C 均值算法用于分割纤维腺体组织。线性回归分析用于比较不同年龄组和种族/民族组之间的平均差异。所得参数呈非正态分布，使用纤维腺体组织体积的自然对数（ln）和密度百分比的平方根进行统计分析。
平均而言，转化后的纤维腺体组织体积和密度百分比随年龄显著降低。在>45 岁的女性中，种族间的平均转化后密度百分比存在差异，但在<45 岁的女性中不存在差异。与白种人和西班牙裔人相比，亚洲人的平均密度百分比较高；在调整年龄后，差异仍然显著，但在调整年龄和乳房体积后，差异不显著。白种人和西班牙裔人之间的密度无显著差异。
使用 MRI 方法分析的结果显示出年龄和种族依赖性，这与使用基于乳房 X 线照相术的方法的文献一致。
