title: Quantitative magnetic resonance imaging parameters and their relationship to mammographic pattern.
abstract: BACKGROUND
  Breast cancer exhibits wide international variation in incidence, which has led to the identification of several factors correlating with the risk of the disease. Magnetic resonance imaging (MRI) techniques can provide quantitative information about the biological and physical properties of tissue.
  
  
  OBJECTIVE
  This work tested several magnetic resonance tissue parameters for their ability to distinguish quantitatively between breast tissues in subjects at substantially different risk for breast cancer as defined indirectly by their parenchymal pattern on mammograms.
  
  
  METHODS
  Quantitative MRI parameters (relative water content, longitudinal relaxation time [T1], and transverse relaxation time [T2]) were measured for breast tissue using newly developed techniques in two groups of women with mammographic parenchymal appearance associated with high (Dy pattern [i.e., extensive nodular or diffuse density]; n = 12) or low (N1 pattern [i.e., breast containing mainly fat]; n = 11) risk of breast cancer.
  
  
  RESULTS
  The two groups have significantly different average relative water content (P less than .0001) and average T1 (P less than .0001). Pixel histograms of T2 values show marked differences between the two groups which can be characterized with a fourth moment parameter.
  
  
  CONCLUSIONS
  Quantitative MRI techniques exhibit good potential for assessing tissue characteristics in the breast that are associated with risk of breast cancer.
  
  
  CONCLUSIONS
  Future work will address the direct correlation of MRI parameters with risk of breast cancer.
authors.affiliation: Sunnybrook Health Science Centre, University of Toronto, Canada.
authors.forename: C S
authors.initials: CS
authors.lastname: Poon
authors.forename: M J
authors.initials: MJ
authors.lastname: Bronskill
authors.forename: R M
authors.initials: RM
authors.lastname: Henkelman
authors.forename: N F
authors.initials: NF
authors.lastname: Boyd
mesh_terms: D000328:Adult; D001834:Body Water; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008327:Mammography; D008875:Middle Aged; D010865:Pilot Projects