Rheumatoid arthritis of the hand and wrist: comparison of three imaging techniques.
OBJECTIVE
The purpose of this study was to compare the relative results from conventional high-field-strength 1.5-T MRI, 0.2-T low-field-strength dedicated extremity MRI, and radiography to detect and grade bone erosions, joint-space narrowing, and synovitis in the hands and wrists of patients with rheumatoid arthritis.


METHODS
Eighteen patients with rheumatoid arthritis underwent conventional high-field-strength MRI, low-field-strength dedicated extremity MRI, and conventional radiography of both hands and wrists. Two independent reviewers searched for the presence and extent of bone erosions, joint-space narrowing, and synovitis. Bone erosions (E scores) and joint-space narrowing (J scores) were evaluated at 14 and 13 sites, respectively, on conventional high-field-strength MRI, low-field-strength dedicated extremity MRI, and radiography, using the Sharp-Genant scoring system. Synovitis (S scores) were evaluated at 13 sites on conventional high-field-strength MRI and low-field-strength dedicated extremity MRI.


RESULTS
For the detection of bone erosions, we found no significant difference (p = 0.71) between conventional high-field-strength MRI (mean +/- SD E score, 27.5 +/- 9.8) and low-field-strength dedicated extremity MRI (28.8 +/- 10.0), but a significant difference (p < 0.001) appeared between MRI and radiography (13.1 +/- 8.3). J scores derived from MRI (conventional high-field-strength MRI, 15.2 +/- 8.3; low-field-strength dedicated extremity MRI, 14.5 +/- 10.4) were higher than those derived from radiography (12.7 +/- 9.6), although the difference was not significant (p = 0.70). Conventional high-field-strength MRI (S score, 35.1 +/- 8.6) and low-field-strength dedicated extremity MRI (30.8 +/- 10.2) were equivalent (p = 0.14) for the evaluation of synovitis. The interobserver agreement for MRI scores was good to excellent (intraclass correlation coefficients, 0.83-0.94).


CONCLUSIONS
Conventional high-field-strength MRI and low-field-strength dedicated extremity MRI showed similar results in terms of cross-sectional grading of bone erosions, joint-space narrowing, and synovitis in the hands and wrists of patients with rheumatoid arthritis.
Taouli
Bachir
B
Department of Radiology, University of California, San Francisco, 505 Parnassus Ave., Box 0628, San Francisco, CA 94143-0628, USA.
Zaim
Souhil
S
Peterfy
Charles G
CG
Lynch
John A
JA
Stork
Alexander
A
Guermazi
Ali
A
Fan
Bo
B
Fye
Kenneth H
KH
Genant
Harry K
HK
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000175:diagnosis*; D001862:Bone Resorption / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D005384:Finger Joint / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012720:Severity of Illness Index; D013585:Synovitis / Q000175:diagnosis* / Q000209:etiology; D014955:Wrist Joint / Q000000981:diagnostic imaging* / Q000473:pathology*