TF and metastatic malignant neoplasm in the lymph nodes: The MRI results indicated that the T2 relaxation rate of Tf-SPIONs was 64.3 S−1 mM−1,thus being higher than that of MRI contrast agent Combidex ® (53.1 S−1 mM−1), which was used in clinical studies for the detection of lymph node metastasis [22].