Disease and Treatment Monitoring

The objective of this chapter is to summarize the current state of knowledge on the use of DWI to assess treatment response for patients receiving neoadjuvant chemotherapy for breast cancer. General methodologies are described for measuring breast tissue diffusion parameters, with particular focus on the serial measurement of these parameters over treatment and the concomitant challenges in achieving standardization. Quantitative metrics such as mean, histogram percentiles, and texture features of apparent diffusion coefficient (ADC) maps are reviewed, as well as more advanced techniques including intravoxel incoherent motion (IVIM) and parametric response mapping (PRM). Multicenter clinical trials for testing and standardizing breast DWI metrics for treatment assessment and combined methods using both dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) and diffusion-weighted imaging (DWI) are also discussed. Finally, we consider the challenges and future directions for refining and improving breast DWI for treatment response assessment.