Dose and scanning delay using USPIO for central nervous system macrophage imaging.
OBJECTIVE
In experimental allergic encephalomyelitis (EAE), central nervous system (CNS) macrophage imaging is achievable by MRI using AMI-227 an ultra-small particle iron oxide contrast agent at a dose of 300 micromol/kg Fe. The objective was to test the feasibility at the human recommended dose of 45 micromol/kg Fe.


METHODS
Two groups of EAE rats were tested with AMI-227 using 45 and 300 micromol/kg Fe respectively. Following i.v. injection of AMI-227, they were scanned after a delay of 4-6 and 20-24 h.


RESULTS
With a high dose of AMI-227, all animals showed low signal intensity related to iron-loaded macrophages in the CNS. At low dose no abnormalities were found in the CNS. Furthermore, a delay of 4-6 h failed to demonstrate abnormalities even at high dose.


CONCLUSIONS
Dose, scanning delay after administration and blood half-life are major parameters for T2* CNS macrophage imaging.
Dousset
V
V
Laboratoire de Neurobiologie et Neuroimagerie Expérimentales, Université Victor Segalen Bordeaux 2, France. vincent.dousset@chu-aquitaine.fr
Gomez
C
C
Petry
K G
KG
Delalande
C
C
Caille
J M
JM
D000818:Animals; D001933:Brain Stem / Q000473:pathology; D002490:Central Nervous System / Q000648:ultrastructure*; D002531:Cerebellum / Q000473:pathology; D003287:Contrast Media / Q000008:administration & dosage; D003911:Dextrans; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000175:diagnosis*; D005260:Female; D052203:Ferrosoferric Oxide; D006168:Guinea Pigs; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007275:Injections, Intravenous; D007501:Iron / Q000008:administration & dosage; D008264:Macrophages / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D010087:Oxides / Q000008:administration & dosage; D051381:Rats; D011917:Rats, Inbred Lew
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; C097921:ferumoxtran-10; D007501:Iron; D052203:Ferrosoferric Oxide