Initial clinical experience with dextran-coated superparamagnetic iron oxide for detection of lymph node metastases in patients with head and neck cancer.

PURPOSE: To investigate the efficacy of magnetic resonance (MR) imaging with dextran-coated superparamagnetic iron oxide in the differentiation of metastatic and benign nodes in patients with head and neck cancer. MATERIALS AND METHODS: MR imaging was performed before and after intravenous administration of iron oxide in 12 patients. Ninety-one pathologically proved nodes were visually analyzed, and 66 lymph nodes were quantitatively analyzed by measuring signal intensity in visually selected regions of interest. RESULTS: Forty of 42 histologically proved metastatic nodes and 41 of 49 benign nodes were detected, yielding 95% sensitivity and 84% specificity. The signal intensity ratio of benign nodes was substantially lower than that of metastatic nodes, indicating better differentiation of metastatic and benign nodes. Furthermore, 13 of 14 normal-sized nodes were detected. CONCLUSION: MR imaging with iron oxide can enable specific differentiation of metastatic and benign nodes in patients with head and neck cancer. This agent may potentially enhance the detection of metastatic lymph nodes and deserves further investigation.