Fig. 3

Clinical data: A 46-year-old woman with right breast cancer (T3N1). Histologic findings demonstrated grade II invasive ductal carcinoma (luminal B1). Post-operative pathologic findings revealed IDC grade I with low grade DCIS with partial effect to therapy confirmed with BCS(ypT1N1). A The first row is (a–c) Breast MR images prior to neoadjuvant chemotherapy demonstrate a 4.6 × 3.9 cm irregular microlobulated enhancing mass in the left breast on axial post-contrast (a) images restricted diffusion (b) with an ADC value of 0.9 (c). The second row (d–f) Breast MR images during neoadjuvant chemotherapy demonstrate partial regression in size of the previously noted left breast mass, measuring 2.9 × 2.5 cm (d), with still restricted diffusion signal in DWI with ADC value about 1 in images (e, f). Δ diameter of lesion = 37% regression “partial response”. B the first row is 18FDG-PET/CT images prior to neoadjuvant chemotherapy demonstrate a metabolically active 18FDG avid hyper-dense irregular microlobulated mass in the left breast on (a) axial CT, (b) axial PET and (c) axial fused PET/CT images (SUVmax = 5.2, SUVmean = 5.2, MTV = 32, TLG = 166). The second row (d–f) 18FDG-PET/CT images during chemotherapy demonstrate metabolic stability, however anatomic regression in the previously detected known left breast mass on (d) axial CT, (e) axial PET and (f) axial fused PET/CT images (SUVmax = 2.47, SUVmean = 10.26, MTV = 8.5, TLG = 86.7. ΔSUVmax = 54% regression) “partial response”