From: Mammographic density and inter-observer variability of pathologic evaluation of core biopsies among women with mammographic abnormalities
ACR category
N
Percent density
Mean
Median
Mostly fatty (ACR I)
58
3
1
Fibroglandular (ACR II)
282
11
8
Heterogeneously dense (ACR III)
283
33
31
Dense (ACR IV)
65
52
50
Missing evaluations
7
22
13
Overall
695
23
18