DCE quantitative measurement plays an important role in the identification of breast tumors. However, different ROI placement can directly affect the inspection results. However, there is no clear standard protocol for clinical routine use. This study aims to evaluate the effect of 2-dimensional maximum diameter (2DMD) and 3-dimensional whole-tumor (3DWT) on quantitative DCE-MRI in differentiating invasive ductal carcinoma (IDC) and breast fibroadenoma which are confirmed by surgical pathology, and determined the more efficient approach for ROI measurement. Our results suggested that 2DMD mean value has more diagnostic performance than 3DWT assessment in distinguishing IDC from fibroadenoma.