title: The influence of increased ambient lighting on mass detection in mammograms.
abstract: OBJECTIVE
  Recent research has provided evidence that in reading rooms equipped with liquid crystal displays (LCDs), a measured increase of ambient lighting may improve clinicians' detection performance. In agreement with this research, the American College of Radiology (ACR) has recommended a moderate increase of ambient lighting in mammography reading rooms. This study was designed to examine the effect of a controlled increase of ambient lighting in mammography reading rooms on the diagnostic performance of breast imaging radiologists.
  
  
  METHODS
  Four breast imaging radiologists read 86 mammograms (43 containing subtle cancerous masses and 43 normal) under low (E = 1 lux) and elevated (E = 50 lux) ambient lighting levels on a Digital Imaging and Communications in Medicine-calibrated, medical-grade LCD. Radiologists were asked to identify cancerous masses and to rate their detection confidence. Observer areas under the curve (AUCs) were calculated using a receiver-operating characteristic analysis of fully paired results. Additionally, average observer selection times under both ambient lighting levels were determined.
  
  
  RESULTS
  Average radiologist AUCs decreased with elevated ambient lighting (0.78 +/- 0.03 to 0.72 +/- 0.04). Observer performance differences, however, were of the same order of magnitude as interobserver variability and were not statistically significant. Average selection times under increased ambient lighting remained constant or decreased, with the greatest decrease occurring for false-positive (20.4 +/- 18.9 to 14.4 +/- 9.6 seconds) and true-positive (18.0 +/- 13.8 to 12.9 +/- 9.4 seconds) selections.
  
  
  CONCLUSIONS
  The results agree with those of previous studies in that observer performance differences under a controlled increase of ambient lighting are not statistically significant. On the basis of these findings and ACR guidelines, a moderate increase of ambient lighting in mammography reading rooms is still suggested, but further research with additional cases and observers should be considered.
authors.affiliation: Duke Advanced Imaging Laboratories, Department of , Duke University, Durham, NC, USA.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Pollard
authors.forename: Ehsan
authors.initials: E
authors.lastname: Samei
authors.forename: Amarpreet S
authors.initials: AS
authors.lastname: Chawla
authors.forename: Jay
authors.initials: J
authors.lastname: Baker
authors.forename: Sujata
authors.initials: S
authors.lastname: Ghate
authors.forename: Connie
authors.initials: C
authors.lastname: Kim
authors.forename: Mary S
authors.initials: MS
authors.lastname: Soo
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Hashimoto
mesh_terms: D016477:Artifacts; D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D016288:Computer Terminals; D004777:Environment; D005260:Female; D006801:Humans; D008029:Lighting / Q000379:methods*; D008327:Mammography / Q000379:methods*; D015588:Observer Variation; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013647:Task Performance and Analysis; D014796:Visual Perception