Factors Affecting Agreement between Breast Density Assessment Using Volumetric Methods and Visual Analogue Scales

Mammographic density in digital mammograms can be assessed visually or using automated volumetric methods; the aim in both cases is to identify women at greater risk of developing breast cancer, and those for whom mammography is less sensitive. Ideally all methods should identify the same women as having high density, but this is not the case in practice. 6422 women were ranked from the highest to lowest density by three methods: QuantraTM, VolparaTM and visual assessment recorded on Visual Analogue Scales. For each pair of methods the 20 cases with the greatest agreement in rank were compared with the 20 with the least agreement. The presence of microcalcifications, skin folds, suboptimally positioned inframammary folds, and whether or not the nipple was in profile were found to affect agreement between methods (p<0.05). Careful positioning during mammographic imaging should reduce discrepancy, but a greater understanding of the relationship between methods is also required.