Evaluation of mammographic density patterns: reproducibility and concordance among scales

BMC Cancer

Table 1 Agreement between the first and second measures using the Wolfe classification

Number of mammograms classified in each category in the first and second measurements
	Second measure
First measure	N1	P1	P2	DY	Total
N1	12	9	0	0	21
P1	4	139	13	5	161
P2	0	7	101	14	122
DY	0	2	13	56	71
Total	16	157	127	75	375
Kappa-statistic estimation
Agreement		Kappa (95% CI)	Weighted Kappa (95% CI)	Kappa high/low risk (95% CI)
Observed %	Expected %
82.13	33.02	0.733 (0.674-0.789)	0.835 (0.784-0.876)	0.851 (0.798-0.904)

Low risk categories:
N1: Breast composed almost completely of fat, with perhaps just a few fibrous connective tissue strands.
P1: Breast composed mainly of fat, although up to a quarter of the sub-areolar area may show beaded or cord-like areas corresponding to prominent ducts.
High risk categories:
P2: More severe involvement of the breast, with a prominent duct pattern occupying more than one quarter of breast volume.
DY: Breast typically contains extensive regions of homogeneous mammographic densities, which appear as sheet-like regions. The proportion of density is greater than that of the fat.

ISSN: 1471-2407