Contrast-enhanced dynamic magnetic resonance imaging of finger joints in osteoarthritis and rheumatoid arthritis: an analysis based on pharmacokinetic modeling.
OBJECTIVE
To investigate a two-compartment kinetic model applied to the dynamic time course of contrast enhancement as a method to differentiate between finger-joint synovitis in established osteoarthritis (OA) and rheumatoid arthritis (RA).


METHODS
Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) of one hand in 19 patients and six healthy volunteers was undertaken. Eight patients had OA of the hand and eleven patients had RA. From the signal intensity curves, the three parameters Kps (endothelial transfer constant), Kep (elimination rate constant from extracellular space back to plasma) and Kel (elimination rate constant from plasma by renal excretion) were calculated.


RESULTS
The rate constant Kps showed the best separation between the groups with significantly higher values in the RA group compared to the OA group (P<0.005) and in the OA group compared to the control group (P<0.005). Significantly higher values of Kep were also found in the RA group compared with the OA group (P<0.005).


CONCLUSIONS
DCE-MRI may provide useful information that can help differentiate synovitis in OA from synovitis in RA.
Kirkhus
E
E
Department of Radiology, Rikshospitalet University Hospital, Oslo, Norway. eva.kirkhus@rikshospitalet.no
Bjørnerud
A
A
Thoen
J
J
Johnston
V
V
Dale
K
K
Smith
H-J
HJ
D001172:Arthritis, Rheumatoid / Q000175:diagnosis*; D003287:Contrast Media / Q000493:pharmacokinetics; D005384:Finger Joint; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008962:Models, Theoretical; D010003:Osteoarthritis / Q000175:diagnosis*; D013585:Synovitis / Q000175:diagnosis / Q000378:metabolism
D003287:Contrast Media