Evaluation of mammographic density patterns: reproducibility and concordance among scales

Abstract

BackgroundIncreased mammographic breast density is a moderate risk factor for breast cancer. Different scales have been proposed for classifying mammographic density. This study sought to assess intra-rater agreement for the most widely used scales (Wolfe, Tabár, BI-RADS and Boyd) and compare them in terms of classifying mammograms as high- or low-density.MethodsThe study covered 3572 mammograms drawn from women included in the DDM-Spain study, carried-out in seven Spanish Autonomous Regions. Each mammogram was read by an expert radiologist and classified using the Wolfe, Tabár, BI-RADS and Boyd scales. In addition, 375 mammograms randomly selected were read a second time to estimate intra-rater agreement for each scale using the kappa statistic. Owing to the ordinal nature of the scales, weighted kappa was computed. The entire set of mammograms (3572) was used to calculate agreement among the different scales in classifying high/low-density patterns, with the kappa statistic being computed on a pair-wise basis. High density was defined as follows: percentage of dense tissue greater than 50% for the Boyd, "heterogeneously dense and extremely dense" categories for the BI-RADS, categories P2 and DY for the Wolfe, and categories IV and V for the Tabár scales.ResultsThere was good agreement between the first and second reading, with weighted kappa values of 0.84 for Wolfe, 0.71 for Tabár, 0.90 for BI-RADS, and 0.92 for Boyd scale. Furthermore, there was substantial agreement among the different scales in classifying high- versus low-density patterns. Agreement was almost perfect between the quantitative scales, Boyd and BI-RADS, and good for those based on the observed pattern, i.e., Tabár and Wolfe (kappa 0.81). Agreement was lower when comparing a pattern-based (Wolfe or Tabár) versus a quantitative-based (BI-RADS or Boyd) scale. Moreover, the Wolfe and Tabár scales classified more mammograms in the high-risk group, 46.61 and 37.32% respectively, while this percentage was lower for the quantitative scales (21.89% for BI-RADS and 21.86% for Boyd).ConclusionsVisual scales of mammographic density show a high reproducibility when appropriate training is provided. Their ability to distinguish between high and low risk render them useful for routine use by breast cancer screening programs. Quantitative-based scales are more specific than pattern-based scales in classifying populations in the high-risk group.

Determinants of the reliability of ultrasound tomography sound speed estimates as a surrogate for volumetric breast density

“…[30][31][32][33][34][35] Most disagreements reflect imprecise separation of the two intermediate density categories, scattered fibroglandular and heterogeneously dense, which are the predominant categories in the general population, T II. (A) Percent variation in sound speed and change in sound speed attributable to covariates and (B) ICC for the experienced rater's repeat reads for sound speed and change in sound speed.…”

Genome wide association study identifies a novel putative mammographic density locus at 1q12‐q21

“…27,43 In our study, three of the seven screening centers used full-field digital images. Furthermore, the use of a single radiologist, with a good intra-observed reproducibility, 19 minimized the measurement error in our study. Moreover, using the same procedure, we have found a significant association between visual estimation of MD and subsequent cancer risk.…”

“…For quality control purposes, a random sample of 374 mammograms was analyzed in duplicate showing a high concordance between both readings (weighted kappa value of 0.92). 19 Two-stage GWAS (DDM-Spain): DNA extraction, genotyping Genomic DNA was extracted from saliva using Oragene DNA Collection Kit (DNAgenotek), and DNA was quantified using PicoGreen (Invitrogen Corp., Carlsbad, CA).…”

Reported Mammographic Density: Film-Screen versus Digital Acquisition

“…It appears that radiologists may be making adjustments in the application of density categories to accommodate for the acquisition method. There is moderate to substantial intra-and interreader agreement in assignment of BI-RADS density categories (27)(28)(29)(30). The variability in reporting of BI-RADS breast density categories will have some effect on the estimation of risk if used in breast cancer risk models.…”