At 24 h after injection of ferumoxytol, MR images demonstrated variable hypointense (dark) T2‐enhancement of the tumor tissue (Fig. 2B): Compared to precontrast images, quantitative T2 relaxation times were significantly decreased by 1.3‐fold after IgG treatment (P = 0.04), 1.6‐fold after doxorubicin treatment (P = 0.02), 2‐fold after CD47 treatment (P = 0.02), and 5.3‐fold decreased after doxorubicin plus CD47 mAb combination therapy (P = 0.01), indicating increasing nanoparticle retention in TAM (Fig. 2B,C). Here, CD47 is linked to neoplasm.