Integration of quantitative DCE-MRI and ADC mapping to monitor treatment response in human breast cancer: initial results

Purpose: The objective of this study was to assess changes in the water apparent diffusion coefficient (ADC) and in pharmacokinetic parameters obtained from the fast-exchange regime (FXR) modeling of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) during neoadjuvant chemotherapy in breast cancer. Materials and Methods: Eleven patients with locally advanced breast cancer underwent MRI examination prior to and after chemotherapy but prior to surgery. A 1.5-T scanner was used to obtain T-1, ADC and DCE-MRI data. DCE-MRI data were analyzed by the FXR model returning estimates of K-trans (volume transfer constant), v(e) (extravascular extracellular volume fraction) and tau(i) (average intracellular water lifetime). Histogram and correlation analyses assessed parameter changes post-treatment. Results: Significant (P <.05) changes or trends towards significance (P <.10) were seen in all parameters except tau(i), although there was qualitative reduction in tau(i) values post-treatment. In particular, there was reduction (P <.035) in voxels with K-trans values ill the range 0.2-0.5 min(-1) and a decrease (P <.05) in voxels with ADC values in the range 0.99 x 10(-3) to 1.35 x 10(-3) mm(2)/s. ADC and nu(e) were negatively correlated (r=-60, P <.02). Parameters sensitive to water distribution and geometry (T-1, nu(e), tau(i) and ADC) correlated with a multivariable linear regression model. Conclusion: The analysis presented here is sensitive to longitudinal changes in breast tumor status; K-trans and ADC are most sensitive to these changes. Relationships between parameters provide information on water distribution and geometry in the tumor environment. (c) 2007 Elsevier Inc. All rights reserved.