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MRI of arthritis: Comparison of ultrasmall superparamagnetic iron oxide vs. Gd‐DTPA
Author(s) -
Simon Gerhard H.,
von VopeliusFeldt Johannes,
Wendland Michael F.,
Fu Yanjun,
Piontek Guido,
Schlegel Juergen,
Chen MeiHsiu,
DaldrupLink Heike E.
Publication year - 2006
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.20556
Subject(s) - monoarthritis , medicine , nuclear medicine , synovitis , magnetic resonance imaging , significant difference , histopathology , arthritis , radiology , pathology
Purpose To compare the ability of the ultrasmall superparamagnetic iron oxide (USPIO) SHU555C vs. gadopentetate dimeglumine (Gd‐DTPA) to detect antigen‐induced monoarthritis with MRI. Materials and Methods Twelve seven‐week‐old female rats with an antigen‐induced monoarthritis of the right knee were randomly assigned to two groups. Animals in group I ( N = 6) underwent MRI using T1‐weighted gradient‐echo sequences before injection and at 2, 9, 17, 25, 33, 40, 47, 55, and 63 minutes postinjection (p.i.) of Gd‐DTPA on day 1, and before injection and at 3, 23, 43, and 123 minutes p.i. of SHU555C on day 2. Animals in group II ( N = 6) were imaged before injection and at 3, 23, 43, and 123 minutes p.i. using identical sequences. Signal‐to‐noise ratios (SNRs) and relative enhancement (ΔSI%) of arthritic and normal synovium were determined from region‐of‐interest (ROI) measurements in consensus reading by two experienced radiologists. Data were tested for significant differences between the two agents and between the arthritic and normal knees using a mixed‐effect model and F‐tests ( P < 0.05). Joints were processed for histopathology as the gold standard. Results USPIO and Gd‐DTPA showed significant enhancement differences ( P < 0.001). USPIO provided a progressive and persistent enhancement of arthritic joints while Gd‐DTPA provided an early and rapidly declining enhancement. Maximal enhancement in synovitis was 400% at 40–120 minutes p.i. of USPIO vs. 300% at two minutes p.i. of Gd‐DTPA. USPIO provided a significant higher difference in enhancement between the arthritic and normal synovium than Gd‐DTPA ( P < 0.001). Histopathology confirmed marked inflammatory synovial changes in all arthritis‐induced right knee joints and normal synovium in all left knee joints. Conclusion Both USPIO and Gd‐DTPA detect arthritis by positive T1‐enhancement. Compared to standard Gd‐DTPA, the USPIO SHU555C provides a comparable maximal T1‐enhancement (at two minutes p.i for Gd‐DTPA and between 43 and 123 minutes p.i. for SHU555C), but in addition it provides a prolonged T1‐enhancement of synovitis and a higher difference between the relative enhancement of arthritic and normal synovium. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.