title: Breast DCE-MRI: influence of postcontrast timing on automated lesion kinetics assessments and discrimination of benign and malignant lesions.
abstract: OBJECTIVE
  Breast dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) scanning protocols vary widely. The purpose of this study was to determine the effects of postcontrast timing on delayed-phase lesion kinetics assessment and ability to discriminate malignant from benign lesions.
  
  
  METHODS
  Following institutional review board approval, we retrospectively reviewed all lesions assessed on magnetic resonance examinations from April 2005 to June 2006. DCE-MRI was performed with 90-second temporal resolution. Delayed-phase kinetic parameters including percentages of persistent, plateau, and washout, and categorizations of predominant and worst curve type were compared between 4.5 and 7.5 minutes postcontrast. Ability to discriminate benign and malignant lesions based on delayed-phase kinetic parameters was compared between postcontrast timings by receiver operating characteristic (ROC) analysis.
  
  
  RESULTS
  Two hundred eighty consecutive breast lesions (206 malignant and 74 benign) were evaluated in 228 women. Comparing kinetics assessments at 7.5 versus 4.5 minutes: volume percentage of washout increased in malignancies by a mean of 9.4% (P<.0001) and increased slightly in benign lesions (mean 3.2%, P=.007); predominant curve type categorizations changed significantly only for malignancies (P<.0001); and worst curve categorizations did not change significantly for either benign or malignant lesions (P>.05). There were no significant differences between timings in area under ROC curves for delayed-phase kinetic parameters.
  
  
  CONCLUSIONS
  The choice of delayed postcontrast timing more strongly affects the kinetics assessments for malignancies than benign breast lesions, but our results suggest that a shortened breast DCE-MRI protocol may not significantly impact diagnostic accuracy. Furthermore, worst curve type classifications are least affected by postcontrast timing and may provide reliable assessment of delayed-phase kinetics across protocols.
authors.affiliation: Department of Radiology- University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Avenue East, G3-200, Seattle, WA 98109-1023. Electronic address: scp3@u.washington.edu.
authors.forename: Savannah C
authors.initials: SC
authors.lastname: Partridge
authors.affiliation: Department of Radiology- University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Avenue East, G3-200, Seattle, WA 98109-1023; Breast Imaging, Radia, Everett, Washington.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Stone
authors.affiliation: Department of Radiology- University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Avenue East, G3-200, Seattle, WA 98109-1023; Department of Radiology, University of Wisconsin, Madison, Wisconsin.
authors.forename: Roberta M
authors.initials: RM
authors.lastname: Strigel
authors.affiliation: Department of Radiology- University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Avenue East, G3-200, Seattle, WA 98109-1023; Department of Radiology, University of Wisconsin, Madison, Wisconsin.
authors.forename: Wendy B
authors.initials: WB
authors.lastname: DeMartini
authors.affiliation: Department of Radiology- University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Avenue East, G3-200, Seattle, WA 98109-1023.
authors.forename: Sue
authors.initials: S
authors.lastname: Peacock
authors.affiliation: Department of Radiology- University of Washington, Seattle Cancer Care Alliance, 825 Eastlake Avenue East, G3-200, Seattle, WA 98109-1023.
authors.forename: Constance D
authors.initials: CD
authors.lastname: Lehman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000175:diagnosis*; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007700:Kinetics; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D015588:Observer Variation; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013997:Time Factors; D055815:Young Adult
chemical_list: D003287:Contrast Media
keywords: Breast cancer; differential diagnosis; dynamic contrast-enhanced MRI (DCE-MRI); kinetic analysis; magnetic resonance imaging (MRI); postcontrast timing