Ferumoxtran-10, a superparamagnetic iron oxide as a magnetic resonance enhancement agent for imaging lymph nodes: a phase 2 dose study.

BACKGROUND AND PURPOSE Dextran-coated ultrasmall superparamagnetic iron oxide ferumoxtran-10 (Combidex) is used in reticuloendothelial MR imaging. Our purpose was to determine the optimal dose and imaging time for lymph node evaluation. MATERIALS Twenty-four healthy volunteers underwent neck MR imaging before and 6, 12, 24, and 36 hours after receiving 1.1, 1.7, 2.6, or 3.4 mg Fe/kg ferumoxtran-10. Vital signs, serum and urine levels, and adverse events were monitored. Qualitative nodal architecture, size, and signal-intensity changes were assessed on T1-, T2-, and T2*-weighted (fast field-echo 25 degrees or 80 degrees flip angle [FFE-25 or FFE-80]) images. Region-of-interest intensities were measured quantitatively. RESULTS Consistently strong enhancement in normal nodes was found with 24- and 36-hour T2- and T2*-weighted imaging after 2.6 and 3.4 mg Fe/kg doses. No serious adverse events occurred. With 2.6 mg Fe/kg, unblinded (vs blinded) specificities at 24 and 36 hours, respectively, were 100% and 100% (vs 88% and 88%) with T2-weighted, 96% and 96% (vs 73% and 85%) with FFE-25, and 100% and 92% (vs 85% and 88%) with FFE-80 sequences. With 3.4 mg Fe/kg, unblinded (vs blinded) specificities at 24 and 36 hours, respectively, were 89% and 79% (vs 75% and 75%) with T2-weighted, 84% and 79% (vs 95% and 100%) with FFE-25, and 95% and 79% (vs 95% and 80%) with FFE-80 sequences. CONCLUSION Ferumoxtran-10 nodal imaging appears to be effective and safe. Signal intensity and specificity for normal nodes were best 24 or 36 hours after 2.6 and 3.4 mg Fe/kg doses. Nodal conspicuity was best with T2- and T2*-weighted sequences.