Same task, same observers, different values: the problem with visual assessment of breast density

Jamie Sergeant, Lani Walshaw, Mary Wilson, Sita Seed, Nicky Barr, Ursula Beetles, Caroline Boggis, Sara Bundred, Soujanya Gadde, Yit Lim, Sigrid Whiteside, D. Gareth Evans, Anthony Howell, Susan Astley, Craig Abbey (Editor), Claudia Mello-Thoms (Editor)

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


The proportion of radio-opaque fibroglandular tissue in a mammographic image of the breast is a strong and modifiable risk factor for breast cancer. Subjective, area-based estimates made by expert observers provide a simple and efficient way of measuring breast density within a screening programme, but the degree of variability may render the reliable identification of women at increased risk impossible. This study examines the repeatability of visual assessment of percent breast density by expert observers. Five consultant radiologists and two breast physicians, all with at least two years’ experience in mammographic density assessment, were presented with 100 digital mammogram cases for which they had estimated density at least 12 months previously. Estimates of percent density were made for each mammographic view and recorded on a printed visual analogue scale. The level of agreement between the two sets of estimates was assessed graphically using Bland-Altman plots. All but one observer had a mean difference of less than 6 percentage points, while the largest mean difference was 14.66 percentage points. The narrowest 95% limits of agreement for the differences were -11.15 to 17.35 and the widest were -13.95 to 40.43. Coefficients of repeatability ranged from 14.40 to 38.60. Although visual assessment of breast density has been shown to be strongly associated with cancer risk, the lack of agreement shown here between repeat assessments of the same images by the same observers questions the reliability of using visual assessment to identify women at high risk or to detect moderate changes in breast density over time.
Original languageEnglish
Title of host publicationProc. SPIE 8673, Medical Imaging 2013: Image Perception, Observer Performance, and Technology Assessment, 86730T
EditorsCraig Abbey, Claudia Mello-Thoms
Place of PublicationUSA
Publication statusPublished - 2013
EventSPIE Medical Imaging 2013 - Florida, USA
Duration: 1 Jan 1824 → …


ConferenceSPIE Medical Imaging 2013
CityFlorida, USA
Period1/01/24 → …


  • Mammography
  • Visual assessment
  • Breast Density
  • Inter Observer Variability


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