FIGURE 2. Pretherapy (A and B) and posttherapy (C and D) 99mTc-sestamibi studies (lateral views of left breast in prone position) of patient 29, who showed positive response to chemotherapy at pathologic examination. Pretherapy study evidenced very intense and diffuse tracer uptake both in tumor and in axillary nodes in early image (A) and low 99mTc-sestamibi WOR (30%) in delayed image (B), predicting low MDR expression. Early posttherapy image (C) confirmed positive response to chemotherapy, showing small area of residual tracer uptake in tumoral region and evident decrease of tracer uptake in axilla. Uptake remained substantially unmodified in corresponding delayed image (D).
