Percent dense volume and absolute dense volume by BI-RADS density category and by age group.

IQR = inter-quartile range Percent dense volume and absolute dense volume by BI-RADS density category and by age group.IQR：四分位距（inter-quartile range）。 按乳腺影像报告与数据系统（BI-RADS）密度分类及年龄分组划分的致密体积百分比与绝对致密体积。