title: Diffusion-weighted imaging of breast lesions: Region-of-interest placement and different ADC parameters influence apparent diffusion coefficient values.
abstract: OBJECTIVE
  To investigate the influence of region-of-interest (ROI) placement and different apparent diffusion coefficient (ADC) parameters on ADC values, diagnostic performance, reproducibility and measurement time in breast tumours.
  
  
  METHODS
  In this IRB-approved, retrospective study, 149 histopathologically proven breast tumours (109 malignant, 40 benign) in 147 women (mean age 53.2) were investigated. Three radiologists independently measured minimum, mean and maximum ADC, each using three ROI placement approaches:1 - small 2D-ROI, 2 - large 2D-ROI and 3 - 3D-ROI covering the whole lesion. One reader performed all measurements twice. Median ADC values, diagnostic performance, reproducibility, and measurement time were calculated and compared between all combinations of ROI placement approaches and ADC parameters.
  
  
  RESULTS
  Median ADC values differed significantly between the ROI placement approaches (p < .001). Minimum ADC showed the best diagnostic performance (AUC .928-.956), followed by mean ADC obtained from 2D ROIs (.926-.94). Minimum and mean ADC showed high intra- (ICC .85-.94) and inter-reader reproducibility (ICC .74-.94). Median measurement time was significantly shorter for the 2D ROIs (p < .001).
  
  
  CONCLUSIONS
  ROI placement significantly influences ADC values measured in breast tumours. Minimum and mean ADC acquired from 2D-ROIs are useful for the differentiation of benign and malignant breast lesions, and are highly reproducible, with rapid measurement.
  
  
  CONCLUSIONS
  • Region of interest placement significantly influences apparent diffusion coefficient of breast tumours. • Minimum and mean apparent diffusion coefficient perform best and are reproducible. • 2D regions of interest perform best and provide rapid measurement times.
authors: Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors: Hubert
authors: H
authors: Bickel
authors: Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors: Katja
authors: K
authors: Pinker
authors: Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors: Stephan
authors: S
authors: Polanec
authors: Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors: Heinrich
authors: H
authors: Magometschnigg
authors: Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors: Georg
authors: G
authors: Wengert
authors: Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors: Claudio
authors: C
authors: Spick
authors: Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna - MR Center of Excellence, Vienna, Austria.
authors: Wolfgang
authors: W
authors: Bogner
authors: Department of Pathology, Medical University Vienna, Vienna, Austria.
authors: Zsuzsanna
authors: Z
authors: Bago-Horvath
authors: Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria. thomas.helbich@meduniwien.ac.at.
authors: Thomas H
authors: TH
authors: Helbich
authors: Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors: Pascal
authors: P
authors: Baltzer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult
keywords: Breast cancer; Diffusion magnetic resonance imaging; Magnetic resonance imaging; Molecular imaging; Reproducibility of results and findings