title: Diffusion-weighted imaging: Effects of intravascular contrast agents on apparent diffusion coefficient measures of breast malignancies at 3 Tesla.
abstract: BACKGROUND
  To determine whether apparent diffusion coefficient (ADC) measures of breast lesions at 3 Tesla (T) are affected by gadolinium administration.
  
  
  METHODS
  The study included 19 patients who underwent 3T MRI. Diffusion-weighted imaging (DWI) was acquired with b = 0, 100, and 800 s/mm(2) before and after a dynamic contrast-enhanced (DCE) sequence. ADC values were measured for each lesion and normal fibroglandular tissue. Pre- and postcontrast ADC measures were compared by Wilcoxon signed-rank test, and differences between groups were compared by Mann-Whitney U test; P < 0.05 was considered statistically significant.
  
  
  RESULTS
  There was no significant difference in pre- and postcontrast ADC measured at b = 0, 100, 800 s/mm(2) for malignancies (median change: -0.4%, -0.01 × 10(-3) mm(2) /s, P = 0.40), but there was a slight increase in postcontrast ADC in normal tissue (+1.6%, +0.04 × 10(-3) mm(2) /s, P = 0.0006). Findings were similar for both lesions (-0.4%, -0.01 × 10(-3) mm(2) /s, P = 0.54) and normal tissue (+1.5%, +0.03 × 10(-3) mm(2) /s, P = 0.002) with ADC measured at b = 0,800 and also at b = 100, 800 s/mm(2) (lesions: +0.9%, +0.01 × 10(-3) mm(2) /s, P = 0.71; normal tissue: +1.8%, +0.03 × 10(-3) mm(2) /s, P = 0.005). For lesions, results were not affected by lesion size, type (mass versus nonmass enhancement), mean initial enhancement, late enhancement, or delayed enhancement rate on DCE-MRI (P > 0.05 for all). Normal tissue showed some trends with greater progressive enhancement rates and higher late enhancement levels correlating with greater increase in postcontrast ADC (P = 0.09 for both).
  
  
  CONCLUSIONS
  Our results show that breast lesion ADC measures using our approach were not significantly altered following DCE-MRI at 3T, suggesting DWI and DCE-MRI can be performed in any order without affecting diagnostic criteria. However, influences of contrast on ADC measures in normal breast tissue were observed and require further investigation.
authors.affiliation: Department of Radiology, University of Washington, Seattle, Washington, USA.
authors.forename: Vicky T
authors.initials: VT
authors.lastname: Nguyen
authors.affiliation: Department of Radiology, University of Washington, Seattle, Washington, USA.|Seattle Cancer Care Alliance, 825 Eastlake Ave E, G3-200, Seattle, Washington, USA.
authors.forename: Habib
authors.initials: H
authors.lastname: Rahbar
authors.affiliation: Department of Radiology, University of Washington, Seattle, Washington, USA.|Seattle Cancer Care Alliance, 825 Eastlake Ave E, G3-200, Seattle, Washington, USA.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Olson
authors.affiliation: Department of Radiology, University of Washington, Seattle, Washington, USA.|Seattle Cancer Care Alliance, 825 Eastlake Ave E, G3-200, Seattle, Washington, USA.
authors.forename: Cheng-Liang
authors.initials: CL
authors.lastname: Liu
authors.affiliation: Department of Radiology, University of Washington, Seattle, Washington, USA.|Seattle Cancer Care Alliance, 825 Eastlake Ave E, G3-200, Seattle, Washington, USA.
authors.forename: Constance D
authors.initials: CD
authors.lastname: Lehman
authors.affiliation: Department of Radiology, University of Washington, Seattle, Washington, USA.|Seattle Cancer Care Alliance, 825 Eastlake Ave E, G3-200, Seattle, Washington, USA.
authors.forename: Savannah C
authors.initials: SC
authors.lastname: Partridge
mesh_terms: D000328:Adult; D000465:Algorithms; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D002138:Calibration; D003287:Contrast Media / Q000737:chemistry*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005682:Gadolinium / Q000737:chemistry*; D019786:Gadolinium DTPA / Q000737:chemistry; D064368:Healthy Volunteers; D006571:Heterocyclic Compounds / Q000737:chemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008875:Middle Aged; D009942:Organometallic Compounds / Q000737:chemistry; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C062402:gadoteridol; D005682:Gadolinium; D019786:Gadolinium DTPA
keywords: apparent diffusion coefficient; breast cancer; diffusion-weighted imaging; gadolinium; magnetic resonance imaging