title: Consistency of breast density categories in serial screening mammograms: A comparison between automated and human assessment.
abstract: Reliable breast density measurement is needed to personalize screening by using density as a risk factor and offering supplemental screening to women with dense breasts. We investigated the categorization of pairs of subsequent screening mammograms into density classes by human readers and by an automated system. With software (VDG) and by four readers, including three specialized breast radiologists, 1000 mammograms belonging to 500 pairs of subsequent screening exams were categorized into either two or four density classes. We calculated percent agreement and the percentage of women that changed from dense to non-dense and vice versa. Inter-exam agreement (IEA) was calculated with kappa statistics. Results were computed for each reader individually and for the case that each mammogram was classified by one of the four readers by random assignment (group reading). Higher percent agreement was found with VDG (90.4%, CI 87.9-92.9%) than with readers (86.2-89.2%), while less plausible changes from non-dense to dense occur less often with VDG (2.8%, CI 1.4-4.2%) than with group reading (4.2%, CI 2.4-6.0%). We found an IEA of 0.68-0.77 for the readers using two classes and an IEA of 0.76-0.82 using four classes. IEA is significantly higher with VDG compared to group reading. The categorization of serial mammograms in density classes is more consistent with automated software than with a mixed group of human readers. When using breast density to personalize screening protocols, assessment with software may be preferred over assessment by radiologists.
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands. Electronic address: Katharina.Holland@radboudumc.nl.
authors.forename: Katharina
authors.initials: K
authors.lastname: Holland
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands. Electronic address: Jan.vanZelst@radboudumc.nl.
authors.forename: Jan
authors.initials: J
authors.lastname: van Zelst
authors.affiliation: LRCB - Dutch Reference Center for Screening, PO Box 6873, 6503 GJ Nijmegen, The Netherlands; Department of Radiology/Biomedical Engineering and Physics, Academic Medical Center Amsterdam, PO Box 22660, 1100 DD Amsterdam, The Netherlands. Electronic address: G.denHeeten@lrcb.nl.
authors.forename: Gerard J
authors.initials: GJ
authors.lastname: den Heeten
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands. Electronic address: Mechli.Imhof-Tas@radboudumc.nl.
authors.forename: Mechli
authors.initials: M
authors.lastname: Imhof-Tas
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands. Electronic address: Ritse.Mann@radboudumc.nl.
authors.forename: Ritse M
authors.initials: RM
authors.lastname: Mann
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, The Netherlands. Electronic address: C.vanGils@umcutrecht.nl.
authors.forename: Carla H
authors.initials: CH
authors.lastname: van Gils
authors.affiliation: Department of Radiology and Nuclear Medicine, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands. Electronic address: Nico.Karssemeijer@radboudumc.nl.
authors.forename: Nico
authors.initials: N
authors.lastname: Karssemeijer
mesh_terms: D000368:Aged; D001940:Breast / Q000000981:diagnostic imaging*; D000071060:Breast Density; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000209:etiology; D002983:Clinical Competence / Q000592:standards*; D055088:Early Detection of Cancer / Q000379:methods / Q000592:standards; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods / Q000592:standards*; D008327:Mammography / Q000592:standards*; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012307:Risk Factors; D012984:Software
keywords: Breast; Computer-assisted; Mammographic density; Mammography; Screening