title: Performance of DWI as a Rapid Unenhanced Technique for Detecting Mammographically Occult Breast Cancer in Elevated-Risk Women With Dense Breasts.
abstract: OBJECTIVE
  The objective of our study was to evaluate the performance of DWI to detect mammographically occult breast cancer in elevated-risk women with dense breasts.
  
  
  METHODS
  We retrospectively reviewed all women who underwent screening breast MRI at our institution from January 2007 through May 2013. We created a case-control cohort composed of 48 subjects with mammographically dense breasts: 24 with mammographically occult cancer detected on MRI and 24 healthy women with negative MRI findings who were matched to the subjects with breast cancer patients for age, breast density, and MRI protocol. The contrast-to-noise ratio (CNR), apparent diffusion coefficient (ADC), and conspicuity score (range, 1-5) were assessed on DWI for all malignancies. Lesions and normal tissue were compared using the Wilcoxon signed rank test; associations with clinical characteristics were evaluated using the Mann-Whitney U test. Three experienced breast imagers who were blinded to medical records and contrast-enhanced MRI findings independently evaluated the unenhanced MRI scans of the 48 women for the presence of cancer.
  
  
  RESULTS
  Mammographically occult breast cancers (invasive carcinoma, n = 16; ductal carcinoma in situ, n = 8) in women with dense breasts typically exhibited higher signal intensity on DWI than normal parenchyma (median CNR of cancers, 1.4; median conspicuity score of cancers, 4) and a lower ADC (median, 1.31 vs 1.79 × 10(-3) mm(2)/s, respectively) (p < 0.0001). The conspicuity score, CNR, and ADC were not associated with patient age, menopausal status, lesion size, morphologic type, or histology (p > 0.05). Average reader performance using unenhanced MRI was 45% sensitivity, 91% specificity, 62% positive predictive value, and 83% negative predictive value.
  
  
  CONCLUSIONS
  In elevated-risk women with dense breasts, DWI can reveal cancers in addition to those detected on mammography alone with a low false-positive rate; these results suggest that DWI may have potential as a rapid supplemental screening tool.
authors.affiliation: 1 Department of Radiology, University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Ave E, Rm G3-200, Seattle, WA 98109-1023.|2 Present address: Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: McDonald
authors.affiliation: 1 Department of Radiology, University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Ave E, Rm G3-200, Seattle, WA 98109-1023.
authors.forename: Jill A
authors.initials: JA
authors.lastname: Hammersley
authors.affiliation: 1 Department of Radiology, University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Ave E, Rm G3-200, Seattle, WA 98109-1023.
authors.forename: Shinn-Huey S
authors.initials: SH
authors.lastname: Chou
authors.affiliation: 1 Department of Radiology, University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Ave E, Rm G3-200, Seattle, WA 98109-1023.
authors.forename: Habib
authors.initials: H
authors.lastname: Rahbar
authors.affiliation: 1 Department of Radiology, University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Ave E, Rm G3-200, Seattle, WA 98109-1023.
authors.forename: John R
authors.initials: JR
authors.lastname: Scheel
authors.affiliation: 1 Department of Radiology, University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Ave E, Rm G3-200, Seattle, WA 98109-1023.
authors.forename: Christoph I
authors.initials: CI
authors.lastname: Lee
authors.affiliation: 1 Department of Radiology, University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Ave E, Rm G3-200, Seattle, WA 98109-1023.
authors.forename: Cheng-Liang
authors.initials: CL
authors.lastname: Liu
authors.affiliation: 1 Department of Radiology, University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Ave E, Rm G3-200, Seattle, WA 98109-1023.
authors.forename: Constance D
authors.initials: CD
authors.lastname: Lehman
authors.affiliation: 1 Department of Radiology, University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Ave E, Rm G3-200, Seattle, WA 98109-1023.
authors.forename: Savannah C
authors.initials: SC
authors.lastname: Partridge
mesh_terms: D000328:Adult; D000368:Aged; D000071060:Breast Density; D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D016022:Case-Control Studies; D002983:Clinical Competence; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media
keywords: DWI; MRI; breast cancer screening; cancer detection; dense breasts; mammographically occult cancer; reader performance