Comparison of diffusion-weighted imaging ADC metrics for early prediction of neoadjuvant treatment response in HER2-negative breast cancer

In breast imaging, diffusion-based (DW) MRI delivers complementary quantitative value to conventional dynamic contrast enhanced MRI. ADC maps of tumor tissue calculated from DW-MRI, specifically mean ADC of the tumor region of interest, have shown promise for measuring early response to neoadjuvant chemotherapy (NAC). However, depending on intra-tumoral heterogeneity, other histogram-based ADC metrics may provide even better predictive performance than mean ADC, but are yet to be studied thoroughly. Here, we investigated nine ADC-based metrics regarding their predictive performance for NAC treatment response.