Evaluation of nonperfused myocardial ischemia with MRI and an intravascular USPIO contrast agent in an ex vivo pig model

High Field Magnetic Resonance Imaging Evaluation of Superparamagnetic Iron Oxide Nanoparticles in a Permanent Rat Myocardial Infarction

“…5,24,25 These results differ from previously published studies where quantifiable signal changes were observed in rats, 14,15 healthy volunteers 26,27 or in a model of myocardial infarction induced in pigs. 16 However, those studies were performed at lower magnetic fields whereas r1 relaxivity of the nanoparticles used in the present study was 36 mmol/L Ϫ1 ·s Ϫ1 at 0.5T and 12 mmol/ L Ϫ1 ·s Ϫ1 at 1.5T. 19 Increasing the field to 7T, lead to a dramatic decrease of this r1 relaxivity (1.2 mmol/L Ϫ1 ·s Ϫ1 ) .…”

Evaluation of tumoral enhancement by superparamagnetic iron oxide particles: comparative studies with ferumoxtran and anionic iron oxide nanoparticles

“…However, no precise description of enhancement mechanisms has been published, notably concerning the respective roles of cellular uptake, and particle extravasation through the tumor interstitium. Extravasation through the interstitium has been implicated in the brightening observed with T1 sequences in tumoral lymph nodes [14] and necrotic myocardium [15], and is due to r1 relaxivity of particles. Interstitial extravasation has not yet been modeled, but may be of major interest for predicting the therapeutic efficacy of high-molecular-weight anticancer drugs.…”

In and Ex Vivo MR Evaluation of Acute Myocardial Ischemia in Pigs by Determining R1 in Steady State After the Administration of the Intravascular Contrast Agent NC100150 Injection

“…We calculated a linear dose response of R1 in perfused myocardium in the studied dose range (0 -5 mg Fe/kg bw), with slope value (b) ϭ 0.143 (mgFe/kg Ϫ1 s Ϫ1 ) in POST images and 0.051 in BOX images. The b value in the POST images is close to that (0.141) reported by Wagenseil et al The b value in the BOX images is on the same level as that previously reported by Bjerner et al, 25 who obtained a value of 0.042 over the dose range 0 -12 mg Fe/kg bw. The less pronounced R1 change in perfused myocardium in the box compared with in vivo is probably a result of water exchange limitations and/or loss of blood.…”

“…[22][23][24] The relaxation rate (R1) in perfused and nonperfused myocardium, after injection of different doses of the intravascular contrast agent NC100150 Injection up to 12 mgFe/kg body weight (bw), has previously been measured in an ex vivo animal model of acute myocardial ischemia. 25 The…”