Ferumoxytol nanoparticles delineate early necrosis on MR images.

<p>Axial T1- and T2*-weighted MR images of 4T1 and PymT tumors in mice before, 1 hour and 24 hours post injection (p.i.) of ferumoxytol at a dose of 0.5 mmol Fe/kg. Note homogenous tumors on pre-contrast images with relatively uniform blood pool enhancement at 1 h p.i.. 4T1 tumors demonstrate marked central T1-enhancement at 24 h p.i..