title: T(2)∗ relaxation times of intraductal murine mammary cancer, invasive mammary cancer, and normal mammary gland.
abstract: OBJECTIVE
  This study investigates the feasibility of T(2)∗ to be a diagnostic indicator of early breast cancer in a mouse model. T(2)∗ is sensitive to susceptibility effects due to local inhomogeneity of the magnetic field, e.g., caused by hemosiderin or deoxyhemoglobin. In these mouse models, unlike in patients, the characteristics of single mammary ducts containing pure intraductal cancer can be evaluated.
  
  
  METHODS
  The C3(1)SV40Tag mouse model of breast cancer (n = 11) and normal FVB∕N mice (n = 6) were used to measure T(2)∗ of normal mammary gland tissue, intraepithelial neoplasia, invasive cancers, mammary lymph nodes, and muscle. MRI experiments were performed on a 9.4T animal scanner. High resolution (117 microns) axial 2D multislice gradient echo images with fat suppression were acquired first to identify inguinal mammary gland. Then a multislice multigradient echo pulse sequence with and without fat suppression were performed over the inguinal mammary gland. The modulus of a complex double exponential decay detected by the multigradient echo sequence was used to fit the absolute proton free induction decay averaged over a region of interest to determine the T(2)∗ of water and fat signals.
  
  
  RESULTS
  The measured T(2)∗ values of tumor and muscle are similar (∼15 ms), and almost twice that of lymph nodes (∼8 ms). There was a statistically significant difference (p < 0.03) between T(2)∗ in normal mammary tissue (13.7 ± 2.9 ms) and intraductal cancers (11 ± 2.0 ms) when a fat suppression pulse was applied.
  
  
  CONCLUSIONS
  These are the first reported T(2)∗ measurements from single mammary ducts. The results demonstrated that T(2)∗ measurements may have utility for identifying early pre-invasive cancers in mouse models. This may inspire similar research for patients using T(2)∗ for diagnostic imaging of early breast cancer.
authors.affiliation: Department of Radiology, University of Chicago, Chicago, IL, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hipp
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Fan
authors.forename: Sanaz A
authors.initials: SA
authors.lastname: Jansen
authors.forename: Erica J
authors.initials: EJ
authors.lastname: Markiewicz
authors.forename: James
authors.initials: J
authors.lastname: Vosicky
authors.forename: Gillian M
authors.initials: GM
authors.lastname: Newstead
authors.forename: Suzanne D
authors.initials: SD
authors.lastname: Conzen
authors.forename: Thomas
authors.initials: T
authors.lastname: Krausz
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Karczmar
mesh_terms: D000818:Animals; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008321:Mammary Glands, Animal / Q000166:cytology* / Q000473:pathology; D015674:Mammary Neoplasms, Animal / Q000175:diagnosis* / Q000473:pathology*; D051379:Mice; D009361:Neoplasm Invasiveness; D013997:Time Factors