Potential of Superparamagnetic Iron Oxide in the Differential Diagnosis of Metastasis and Inflammation in Bone Marrow

RATIONALE AND OBJECTIVES: The utility of ferucarbotran for the diagnosis of bone metastases was investigated using tumor-implanted rabbits. The potential of ferucarbotran in the differential diagnosis of metastasis and inflammation was also investigated. METHODS: Twelve rabbits were divided into 2 groups (tumor and inflammation groups). Six rabbits of tumor group were inoculated with VX2 tumor cell suspension, and the 6 rabbits of the inflammation group were inoculated with 10% croton oil in the bone marrow of the right femur. All rabbits were imaged using a clinical MRI system. Signal intensity in the bone marrow of the right femur was measured in each rabbit before and after the intravenous injection of 8 micromol Fe/kg of ferucarbotran. As a control, the signal intensity in the bone marrow of the left femur (the normal, intact femur) was measured in each rabbit. The change in signal intensity of each group was compared statistically. After MRI imaging, the femora were removed, and sections were prepared for microscopic examination. RESULTS: Signal intensity in the right femur of the tumor group did not change after injection, although that of the inflammation group and the control group decreased. In the histologic findings, tumors were widely spread in the right femur of the tumor group. The infiltration of pseudoeosinocytes was induced in the right femur of the inflammation group. CONCLUSIONS: This animal study showed that ferucarbotran was useful to detect bone marrow tumors. In addition, ferucarbotran may have potential in the differential diagnosis of bone metastasis and some kinds of inflammation.