Figure 4
Imaging MRI and CT. (a) MR imaging contrast of JHU MIONs (1), Si-MIONs (2) and AuSi-MIONs (3). Imaging of gel phantoms over a range of 0–80 μg/ml (0–1.4 mM) based on iron content, showing T2 effect as iron concentration increases (top). T2 relaxation (ms) calculated from spin-echo MR imaging of phantoms (bottom). Inset shows concentration (mM) versus 1/T2, the slope of which gives transverse relaxivity (R2) in units of mM−1 s−1. (b) Signal intensity from MION phantoms over a range of 0–7 mg/ml (based on iron content) demonstrating CT contrast with gold (top). CT contrast, measured in Hounsfield units (HU), was calculated for each sample and were plotted versus iron concentration (bottom).
