Figure 1

Phantom studies with ferumoxytol and ferumoxytol aggregates. Image of an agarose phantom with increasing concentrations of ferumoxytol (left stack) or ferumoxytol concanavalin A (ConA) aggregates (right stack) and the corresponding mu-map. On the VIBE-based MR-derived mu-map, a value of 1,000 reflects soft tissue density and 0 air density. Up to concentrations of 10 mg/kg, the measured value in both phantoms with ferumoxytol and ferumoxytol aggregates was similar, at a value of 854 reflecting fat tissue density. However, significant artifacts in the VIBE-based mu-map due to ferumoxytol aggregates are visible at the concentration of 20 mg/kg, where the content of the agarose phantom is misclassified as air (value of 0) in the VIBE-based mu-map, whereas at the concentration of 10 mg/kg, the observed value is actually higher (1,000) for the ferumoxytol aggregates compared to ferumoxytol alone.