title: Relating Doses of Contrast Agent Administered to TIC and Semi-Quantitative Parameters on DCE-MRI: Based on a Murine Breast Tumor Model.
abstract: OBJECTIVE
  To explore the changes in the time-signal intensity curve(TIC) type and semi-quantitative parameters of dynamic contrast-enhanced(DCE)imaging in relation to variations in the contrast agent(CA) dosage in the Walker 256 murine breast tumor model, and to determine the appropriate parameters for the evaluation ofneoadjuvantchemotherapy(NAC)response.
  
  
  METHODS
  Walker 256 breast tumor models were established in 21 rats, which were randomly divided into three groups of7rats each. Routine scanning and DCE-magnetic resonance imaging (MRI) of the rats were performed using a 7T MR scanner. The three groups of rats were administered different dosages of the CA0.2mmol/kg, 0.3mmol/kg, and 0.5mmol/kg, respectively; and the corresponding TICs the semi-quantitative parameters were calculated and compared among the three groups.
  
  
  RESULTS
  The TICs were not influenced by the CA dosage and presented a washout pattern in all of the tumors evaluated and weren't influenced by the CA dose. The values of the initial enhancement percentage(Efirst), initial enhancement velocity(Vfirst), maximum signal(Smax), maximum enhancement percentage(Emax), washout percentage(Ewash), and signal enhancement ratio(SER) showed statistically significant differences among the three groups (F = 16.952, p = 0.001; F = 69.483, p<0.001; F = 54.838, p<0.001; F = 12.510, p = 0.003; F = 5.248, p = 0.031; F = 9.733, p = 0.006, respectively). However, the values of the time to peak(Tpeak), maximum enhancement velocity(Vmax), and washout velocity(Vwash)did not differ significantly among the three dosage groups (F = 0.065, p = 0.937; F = 1.505, p = 0.273; χ2 = 1.423, p = 0.319, respectively); the washout slope(Slopewash), too, was uninfluenced by the dosage(F = 1.654, p = 0.244).
  
  
  CONCLUSIONS
  The CA dosage didn't affect the TIC type, Tpeak, Vmax, Vwash or Slopewash. These dose-independent parameters as well as the TIC type might be more useful for monitoring the NAC response because they allow the comparisons of the DCE data obtained using different CA dosages.
authors.affiliation: Radiology department, Second Hospital of Tianjin Medical University, Hexi District, Tianjin, China.
authors.forename: Menglin
authors.initials: M
authors.lastname: Wu
authors.affiliation: Department of General surgery, Tianjin Medical University General Hospital, Heping District, Tianjin, China.
authors.forename: Li
authors.initials: L
authors.lastname: Lu
authors.affiliation: Radiology department, Second Hospital of Tianjin Medical University, Hexi District, Tianjin, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Radiology department, Second Hospital of Tianjin Medical University, Hexi District, Tianjin, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Guo
authors.affiliation: Radiology department, Second Hospital of Tianjin Medical University, Hexi District, Tianjin, China.
authors.forename: Feixiang
authors.initials: F
authors.lastname: Zhao
authors.affiliation: Radiology department, Second Hospital of Tianjin Medical University, Hexi District, Tianjin, China.
authors.forename: Tongwei
authors.initials: T
authors.lastname: Li
authors.affiliation: Radiology department, Second Hospital of Tianjin Medical University, Hexi District, Tianjin, China.
authors.forename: Xuening
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000175:diagnosis*; D045744:Cell Line, Tumor; D003287:Contrast Media / Q000008:administration & dosage*; D004195:Disease Models, Animal; D005260:Female; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015674:Mammary Neoplasms, Animal; D051379:Mice
chemical_list: D003287:Contrast Media