Ultrasmall particulate iron oxides as contrast agents for magnetic resonance spectroscopy: a dose-effect study.
Long-distance effects of a superparamagnetic contrast agent (AMI227) were investigated by phosphorus-31 NMR spectroscopy at 7.05 Tesla. In an initial methodological approach, the effects observed on phantoms were compared to the results of theoretical calculations. In a second step, the particles were administered to excised and perfused rat livers (N = 5) and hearts (N = 5) through the perfusion medium for 12 minutes at various concentrations (0.9, 1.8, and 3.6 mM Fe). Organs were subsequently rinsed with the perfusion medium for 42 minutes. During particle perfusion, the spectral lines were shifted and exhibited a strong broadening, although the peak area remained constant, testifying to the inocuity of the material. For hearts only, these disturbances disappeared upon organ rinsing. These through-space susceptibility effects of the particles located in the vessels on phosphorus nuclei, which are strictly confined to the intracellular space, show that high-susceptibility intravascular agents could be useful to evaluate tissue perfusion by contrast-enhanced spectroscopy.
INSERM U438, CHU, BP217, 38043 Grenoble cedex, France.
G
G
Le Duc
L
L
Vander Elst
J M
JM
Colet
A
A
Roch
P
P
Gillis
J F
JF
Le Bas
R N
RN
Muller
D000704:Analysis of Variance; D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage*; D003911:Dextrans; D004305:Dose-Response Relationship, Drug; D052203:Ferrosoferric Oxide; D007501:Iron / Q000008:administration & dosage*; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010087:Oxides / Q000008:administration & dosage*; D019047:Phantoms, Imaging; D010759:Phosphorus Isotopes; D051381:Rats; D017208:Rats, Wistar
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D010759:Phosphorus Isotopes; C097921:ferumoxtran-10; D007501:Iron; D052203:Ferrosoferric Oxide