title: MR imaging of antigen-induced arthritis with a new, folate receptor-targeted contrast agent.
abstract: The purpose of this study was to investigate if the new folate receptor-targeted Gd-chelate P866 may enhance immune-mediated arthritis. A monoarthritis was induced in the right knee of 15 Sprague-Dawley rats. MR imaging of both knees was performed at 2 T before and up to 2 h and 24 h after injection (p.i.) of P866 (n = 3 dose finding study and n = 6, 0.02 mmol Gd/kg), the non-FR targeted P866 analog P1001 (n = 3 at 24 h after P866-administration, 0.02 mmol Gd/kg) or Gd-DOTA (n = 6, 0.1 mmol Gd/kg). Pulse sequences comprised T(1)-SPGR 80 degrees /50 ms/1.7 ms (flip angle/TR/TE) and inversion recovery 10 degrees /3000 ms/1500 ms/50-3050, 10 000 ms (flip angle/TR/TE/TI) sequences. DeltaSI-data and T(1)-relaxation times of arthritic knees and contralateral normal knees were determined. Folate receptor expression was confirmed with histopathology. All three contrast agents showed an initial perfusion effect with significantly higher DeltaSI-data of arthritic knees compared with normal knees (p < 0.05). In addition, P866, but not P1001 or Gd-DOTA, showed a prolonged enhancement of the synovitis. Compared with precontrast values, the T(1)-relaxation times of inflamed synovia were significantly decreased at 2 h p.i. of P866 (p < 0.05), but not P1001 or Gd-DOTA (p > 0.05). Histopathology confirmed the presence of folate receptors in the inflamed joints, but not normal joints. Thus, results suggest a specific accumulation of the folate receptor-targeted Gd-chelate P866 in this arthritis model.
authors: Department of Radiology, UCSF Medical Center, University of California San Francisco, USA.
authors: Olaf
authors: O
authors: Saborowski
authors: Gerhard H
authors: GH
authors: Simon
authors: Hans-Juergen
authors: HJ
authors: Raatschen
authors: Michael F
authors: MF
authors: Wendland
authors: Yanjun
authors: Y
authors: Fu
authors: Tobias
authors: T
authors: Henning
authors: Rick
authors: R
authors: Baehner
authors: Claire
authors: C
authors: Corot
authors: Mei-Hsiu
authors: MH
authors: Chen
authors: Heike E
authors: HE
authors: Daldrup-Link
mesh_terms: D000818:Animals; D000941:Antigens / Q000737:chemistry*; D001168:Arthritis / Q000175:diagnosis / Q000276:immunology* / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry; D003287:Contrast Media / Q000494:pharmacology*; D003952:Diagnostic Imaging / Q000379:methods; D005121:Extremities; D005260:Female; D058973:Folate Receptors, GPI-Anchored; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015233:Models, Statistical; D010477:Perfusion; D010865:Pilot Projects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011956:Receptors, Cell Surface / Q000737:chemistry
chemical_list: D000941:Antigens; D002352:Carrier Proteins; D003287:Contrast Media; D058973:Folate Receptors, GPI-Anchored; D011956:Receptors, Cell Surface