title: Quantitative apparent diffusion coefficient as a noninvasive imaging biomarker for the differentiation of invasive breast cancer and ductal carcinoma in situ.
abstract: OBJECTIVE
  The objective of this study was to evaluate whether apparent diffusion coefficient (ADC) obtained through diffusion-weighted imaging magnetic resonance imaging at 3 T can be used as an imaging biomarker to differentiate invasive breast cancer from noninvasive ductal carcinoma in situ (DCIS).
  
  
  METHODS
  One hundred seventy-six histopathologically verified primary malignant breast tumors were retrospectively evaluated in 170 patients. All patients had undergone a standardized 3-T magnetic resonance imaging protocol, containing a diffusion-weighted sequence with 2 b values and a series of dynamic contrast-enhanced T1-weighted sequences. Apparent diffusion coefficient was measured manually by a reader blinded to the histopathological results. The ADC values were correlated with histopathological results. Mean ADC values were compared between invasive cancers and DCIS as well as between different tumor grades. Receiver operating characteristics curves were used to calculate diagnostic performance.
  
  
  RESULTS
  There were 155 invasive cancers and 21 noninvasive DCIS. Mean (SD) values differed significantly between the invasive cancers (0.9 [0.15] ×10 mm/s) and the DCIS (1.24 [0.23] ×10 mm/s, P < 0.001). Area under the receiver operating characteristics curve was 0.895 (95% confidence interval [CI], 0.840-0.936). A threshold of 1.01 ×10 mm/s or less allowed an identification of invasive cancers with a sensitivity of 78.06% (95% CI, 70.7%-84.3%) and a specificity of 90.5% (95% CI, 69.6%-98.8%). No significant ADC differences were found among different tumor grades (P > 0.05).
  
  
  CONCLUSIONS
  Apparent diffusion coefficient could be used as an imaging biomarker for the diagnosis of breast cancer. It seems to be a valuable noninvasive quantitative biomarker to assess breast cancer invasiveness. Thus, ADC measurements provide the potential to reduce overdiagnosis and subsequent overtreatment.
authors.affiliation: From the *Department of Biomedical Imaging and Image-guided Therapy, †Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy, ‡MR Center of Excellence, Department of Biomedical Imaging and Image-guided Therapy, and §Department of Pathology, Medical University of Vienna, Vienna, Austria.
authors.forename: Hubert
authors.initials: H
authors.lastname: Bickel
authors.forename: Katja
authors.initials: K
authors.lastname: Pinker-Domenig
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bogner
authors.forename: Claudio
authors.initials: C
authors.lastname: Spick
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Bagó-Horváth
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.forename: Thomas
authors.initials: T
authors.lastname: Helbich
authors.forename: Pascal
authors.initials: P
authors.lastname: Baltzer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D015415:Biomarkers; D001943:Breast Neoplasms / Q000473:pathology*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers