The goal of this study was to assess differences in quantitative ADC of breast cancer between ssEPI and rFOV DWI techniques. The two techniques were used to acquire breast DWI images in 27 patients at three different time points during their neoadjuvant chemotherapy. Tumor ADC from the two techniques at baseline and mid-treatment scans show strong correlation and minimal bias. However, tumor ADC from the two techniques at pre-surgery correlated more moderately and showed a slight bias. The relative and absolute changes in ADC at mid-treatment or pre-surgery from baseline showed only moderately-strong non-parametric correlation between the two techniques.