MPO-Gd MRI was successfully used to image inflammation in rabbits with atherosclerosis.25 Moreover, in an animal model of plaque instability, MPO activity was higher in histologically unstable than stable plaque; MPO-Gd retention determined by molecular MRI correlated with plaque destabilization; and genetic or pharmacological blockade of MPO activity increased plaque stability,26,27 thus establishing MPO as causal to plaque destabilization. Here, MPO is linked to atherosclerosis.