Low field dedicated magnetic resonance imaging in untreated rheumatoid arthritis of recent onset.
OBJECTIVE
To compare a low field dedicated extremity magnetic resonance imaging system (E-MRI) with x ray and clinical examination, in the detection of inflammation and erosive lesions in wrist and metacarpophalangeal (MCP) joints in newly diagnosed, untreated rheumatoid arthritis (RA).


METHODS
Twenty five patients (disease duration < or =1 year) and three healthy controls entered the study. An x ray examination and MRI (before and after intravenous injection of a contrast agent) of the 2nd-5th MCP joints and the wrist was performed. The number of erosions on x ray examination and MRI was calculated, and synovitis in the MCP joints and wrists was graded semiquantitatively.


RESULTS
E-MRI detected 57 bone erosions, whereas only six erosions were disclosed by x ray examination (ratio 9.5:1). Synovial hypertrophy grades were significantly higher in RA joints with clinical signs of joint inflammation-that is, swelling and/or tenderness (median 3, 5th-95th centile 1-4) than without these clinical signs (median 2, 5th-95th centile 1-3), p < 0.001. 51% of the joints without clinical signs of synovitis showed synovial hypertrophy on E-MRI. There was a positive correlation between MRI scores of synovitis and the number of erosions detected by MRI in the MCP joints (Spearman r(s) = 0.31, p < 0.01). No healthy controls had erosions or synovitis on MRI.


CONCLUSIONS
Joint destruction starts very early in RA and E-MRI allows detailed evaluation of inflammatory and destructive changes in wrists and MCP joints in patients with incipient RA.
Lindegaard
H
H
Department of Internal Medicine C, Section of Rheumatology, Odense University, Denmark. lindegaard@dadlnet.dk
Vallø
J
J
Hørslev-Petersen
K
K
Junker
P
P
Østergaard
M
M
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000175:diagnosis*; D016022:Case-Control Studies; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008662:Metacarpophalangeal Joint / Q000473:pathology*; D008875:Middle Aged; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D014955:Wrist Joint / Q000473:pathology*
D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA