Assessment of myocardial viability in rats: Evaluation of a new method using superparamagnetic iron oxide nanoparticles and Gd-DOTA at high magnetic field

Abstract

The aim of this study was to detect salvageable peri-infarction myocardium by MRI in rats after infarction, using with a double contrast agent (CA) protocol at 7 Tesla. Intravascular superparamagnetic iron oxide (SPIO) nanoparticles and an extracellular paramagnetic CA (Gd-DOTA) were used to characterize the peri-infarction zone, which may recover function after reperfusion occurs. Infarcted areas measured from T1-weighted (T 1-W) images post Gd-DOTA administration were overestimated compared to histological TTC staining (52% ± 3% of LV surface area vs. 40% ± 3%, P = 0.03) or to T2-W images post SPIO administration (41% ± 4%, P = 0.04), whereas areas measured from T2-W images post SPIO administration were not significantly different from those measured histologically (P = 0.7). Viable and nonviable myocardium portions of ischemically injured myocardium were enhanced after diffusive Gd-DOTA injection. The subsequent injection of vascular SPIO nanoparticles enables the discrimination of viable peri-infarction regions by specifically altering the signal of the still-vascularized myocardium. © 2004 Wiley-Liss, Inc.