title: Ultrasmall supraparamagnetic iron oxide-enhanced magnetic resonance imaging of antigen-induced arthritis: a comparative study between SHU 555 C, ferumoxtran-10, and ferumoxytol.
abstract: 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.
authors.affiliation: Department of Radiology, UCSF Medical Center, University of California, San Francisco, 94143, USA. gerhard.simon@radiology.ucsf.edu
authors.forename: Gerhard H
authors.initials: GH
authors.lastname: Simon
authors.forename: Johannes
authors.initials: J
authors.lastname: von Vopelius-Feldt
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Fu
authors.forename: Juergen
authors.initials: J
authors.lastname: Schlegel
authors.forename: Guido
authors.initials: G
authors.lastname: Pinotek
authors.forename: Michael F
authors.initials: MF
authors.lastname: Wendland
authors.forename: Mei-Hsiu
authors.initials: MH
authors.lastname: Chen
authors.forename: Heike E
authors.initials: HE
authors.lastname: Daldrup-Link
mesh_terms: 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
chemical_list: 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