Assessing the reproducibility of dynamic contrast enhanced magnetic resonance imaging in a murine model of breast cancer.

Quantitative dynamic contrast enhanced magnetic resonance imaging estimates parameters related to tissue vascularity and volume fractions; additionally, semiquantitative parameters such as the initial area under the curve can be utilized to describe tissue behavior. The aim of this study was to establish the reproducibility of quantitative and semiquantitative analysis of dynamic contrast enhanced magnetic resonance imaging in a murine model of breast cancer. For each animal, a T1-weighted, gradient-echo sequence was used to acquire two sets of dynamic contrast enhanced magnetic resonance imaging data separated by 5 h. Data were acquired at both a 0.05 mm3 (128(2) , n=12) and a 0.2 mm3 (64(2), n=12) resolution, and analysis was performed using both the Tofts-Kety (to estimate Ktrans and ve) and extended Tofts-Kety (Ktrans, ve, and vp) models. Reproducibility analysis was performed for both the center slice and the total tumor volume for all parameters. For the total volume analysis, the repeatability index for Ktrans is 0.073 min(-1) in the standard model analysis and 0.075 min(-1) in the extended model analysis at the 128(2) acquisition. For the 64(2) acquisition, the values are 0.089 and 0.063 min(-1) for the standard and extended models, respectively. The repeatability index for initial area under the curve was 0.0039 and 0.0042 mM min for the 128(2) and 64(2) acquisitions, respectively.