title: Blurred digital mammography images: an analysis of technical recall and observer detection performance.
abstract: OBJECTIVE
  Blurred images in full-field digital mammography are a problem in the UK Breast Screening Programme. Technical recalls may be due to blurring not being seen on lower resolution monitors used for review. This study assesses the visual detection of blurring on a 2.3-MP monitor and a 5-MP report grade monitor and proposes an observer standard for the visual detection of blurring on a 5-MP reporting grade monitor.
  
  
  METHODS
  28 observers assessed 120 images for blurring; 20 images had no blurring present, whereas 100 images had blurring imposed through mathematical simulation at 0.2, 0.4, 0.6, 0.8 and 1.0 mm levels of motion. Technical recall rate for both monitors and angular size at each level of motion were calculated. χ2tests were used to test whether significant differences in blurring detection existed between 2.3- and 5-MP monitors.
  
  
  RESULTS
  The technical recall rate for 2.3- and 5-MP monitors are 20.3% and 9.1%, respectively. The angular size for 0.2- to 1-mm motion varied from 55 to 275 arc s. The minimum amount of motion for visual detection of blurring in this study is 0.4 mm. For 0.2-mm simulated motion, there was no significant difference [χ2(1, N = 1095) = 1.61, p = 0.20] in blurring detection between the 2.3- and 5-MP monitors.
  
  
  CONCLUSIONS
  According to this study, monitors ≤2.3 MP are not suitable for technical review of full-field digital mammography images for the detection of blur. Advances in knowledge: This research proposes the first observer standard for the visual detection of blurring.
authors.affiliation: 1 Department of Radiography, University of Salford, Salford, UK.
authors.forename: Wang Kei
authors.initials: WK
authors.lastname: Ma
authors.affiliation: 2 East Lancashire Breast Screening Unit, Burnley General Hospital, Burnley, UK.
authors.forename: Rita
authors.initials: R
authors.lastname: Borgen
authors.affiliation: 3 Department of Radiography, Countess of Chester Hospital NHS Foundation Trust, Chester, UK.
authors.forename: Judith
authors.initials: J
authors.lastname: Kelly
authors.affiliation: 3 Department of Radiography, Countess of Chester Hospital NHS Foundation Trust, Chester, UK.
authors.forename: Sara
authors.initials: S
authors.lastname: Millington
authors.affiliation: 2 East Lancashire Breast Screening Unit, Burnley General Hospital, Burnley, UK.
authors.forename: Beverley
authors.initials: B
authors.lastname: Hilton
authors.affiliation: 4 Department of Computer Science and Software Engineering, University of Salford, Salford, UK.
authors.forename: Rob
authors.initials: R
authors.lastname: Aspin
authors.affiliation: 5 Department of Sciences and Rehabilitation Technologies, Lisbon School of Health Technology, Lisbon, Portugal.|6 Centro de Investigação em Saúde Pública, Escola Nacional de Saúde Pública, Universidade NOVA de Lisboa, Lisbon, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: Lança
authors.affiliation: 1 Department of Radiography, University of Salford, Salford, UK.|7 Department of Radiography, Karolinska Institute, Stockholm, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Hogg
mesh_terms: D001940:Breast / Q000000981:diagnostic imaging; D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008327:Mammography / Q000379:methods*; D015588:Observer Variation; D015203:Reproducibility of Results; D006113:United Kingdom