Ultrasmall supraparamagnetic iron oxide-enhanced magnetic resonance imaging of antigen-induced arthritis: a comparative study between SHU 555 C, ferumoxtran-10, and ferumoxytol.
OBJECTIVE
We sought to compare the ability of 3 ultrasmall superparamagnetic iron oxides (USPIOs) to detect and characterize antigen-induced arthritis with MR imaging.


METHODS
A monoarthritis was induced in the right knee of 18 rats. The left knee served as a normal control. Knees underwent magnetic resonance (MR) imaging before, up to 2 hours, and 24 hours after injection (p.i.) of 200 mumol Fe/kg SHU 555 C (n= 6), ferumoxtran-10 (n = 6), or ferumoxytol (n = 6), using T2-2D-SE 100/20,40,60,80/90 (TR/TE/flipangle), T2*-3D-spoiled gradient recalled (SPGR) 100/15/38, and T1-3D-SPGR 50/1,7/60 sequences.


RESULTS
Quantitative signal to noise ratio and DeltaSI data of arthritic knees on T1- and T2*-weighted MR images showed no significant differences between the 3 USPIOs (P > 0.05). At 2 hours p.i., SNR and DeltaSI data were significantly increased from baseline on T1-weighted images and significantly decreased on T2*-weighted images (P < 0.001). At 24 hours p.i., the T1-enhancement returned to baseline, whereas the T2*-enhancement remained significantly elevated (P < 0.001). Immunostains demonstrated an USPIO compartmentalization in macrophages in the arthritic synovium.


CONCLUSIONS
Based on the relatively small number of animals in our study group, inflammation in antigen-induced arthritis can be equally detected and characterized with any of the three USPIOs evaluated.
Simon
Gerhard H
GH
Department of Radiology, UCSF Medical Center, University of California, San Francisco, 94143, USA. gerhard.simon@radiology.ucsf.edu
von Vopelius-Feldt
Johannes
J
Fu
Yanjun
Y
Schlegel
Juergen
J
Pinotek
Guido
G
Wendland
Michael F
MF
Chen
Mei-Hsiu
MH
Daldrup-Link
Heike E
HE
D000818:Animals; D003287:Contrast Media; D003911:Dextrans; D005260:Female; D052203:Ferrosoferric Oxide; D007091:Image Processing, Computer-Assisted; D007501:Iron; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000276:immunology; D010087:Oxides; D051381:Rats; D017207:Rats, Sprague-Dawley; D012710:Serum Albumin, Bovine; D013535:Suspensions
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D013535:Suspensions; C097921:ferumoxtran-10; D012710:Serum Albumin, Bovine; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide