translation.en: Mammography relies on differences in the appearance of the tumor from the background tissue, and we've seen that those differences can be obscured in a dense breast.
translation.zh: 造影技术依靠的就是 肿瘤组织与周边组织的突显区别， 我们看到这些区别 在高乳腺密度的乳房中很模糊。