Use of AMI-227 as an oral MR contrast agent.
We report the use of an ultrasmall superparamagnetic iron oxide colloid AMI-227 as an oral contrast agent. Due to the small size, AMI-227 has a larger effect on T1 than larger superparamagnetic iron oxides colloids like ferumoxsil. At 2 T, AMI-227 had an R2/R1 of 11.4 compared with an R2/R1 for the superparamagnetic iron oxide ferumoxsil of 179. The R1s of the two agents were 7.1 and 1.6 mM-1 s-1, for AMI-227 and ferumoxsil, respectively. Due to its smaller R2/R1, orally administered AMI-227 can produce brightening or darkening of the lumen of the GI tract, depending on instrument parameters. At 1 mM Fe, image brightening (2 T, TR = 300, TE = 25) or image darkening of the GI tract (2 T, TR = 1500, TE = 80) was obtained. The ability of AMI-227 to produce either image brightening or darkening suggests it may be useful as an MR contrast agent for the GI tract.
Rogers
J
J
Advanced Magnetics Inc., Cambridge, MA 02138.
Lewis
J
J
Josephson
L
L
D000005:Abdomen / Q000033:anatomy & histology; D000284:Administration, Oral; D000818:Animals; D003287:Contrast Media; D003911:Dextrans; D004064:Digestive System / Q000033:anatomy & histology; D052203:Ferrosoferric Oxide; D019786:Gadolinium DTPA; D007501:Iron / Q000008:administration & dosage; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles; D008297:Male; D009942:Organometallic Compounds; D010087:Oxides / Q000008:administration & dosage; D004369:Pentetic Acid / Q000031:analogs & derivatives; D051381:Rats; D011919:Rats, Inbred Strains; D012828:Silicones; D012833:Siloxanes
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D009942:Organometallic Compounds; D010087:Oxides; D012828:Silicones; D012833:Siloxanes; C097921:ferumoxtran-10; C088769:ferumoxsil; D004369:Pentetic Acid; D007501:Iron; D019786:Gadolinium DTPA; D052203:Ferrosoferric Oxide