Figure 8: A 31-year-old patient with non-mass-like enhancement lesion (invasive ductal cancer with extensive carcinoma in situ components). From (a) to (c), the contrast-enhanced (subtraction) images selected from the same level in pretreatment, F/U-1, and F/U-2 MRI are shown. The tumor boundary cannot be clearly determined, and thus the extent of the tumor cannot be measured precisely. The area of the enhanced tumor tissues and the degree of enhancement are decreasing with treatment, indicating a good response to the chemotherapy. The right panel shows the corresponding color-coded maps analyzed using pixel-by-pixel pharmacokinetic analysis. The post-NAC pathological examination shows scattered cancer cells within a 10 cm region. It is typical for a non-mass lesion to show scattered diseases within the original tumor bed. Despite the decreased cancer cell density responding to NAC, this patient still needs mastectomy.