Assessment of cartilage loss at the wrist in rheumatoid arthritis using a new MRI scoring system.
OBJECTIVE
To develop and test an MRI cartilage scoring system for use at the wrist in rheumatoid arthritis (RA).


METHODS
MRI scans were obtained using a 3T MRI scanner with dedicated wrist coil in 22 early and 16 established RA patients plus 22 controls. Axial and coronal T1-weighted (precontrast and postcontrast) and T2-weighted turbo spin echo sequences were obtained. Eight wrist joints were scored for cartilage narrowing: distal radioulnar, radiolunate, radioscaphoid, triquetrum-hamate, capitate-lunate, scaphotrapezoid, second metacarpal base-trapezoid and third metacarpal base-capitate, using a system based on the Sharp van der Heijde x-ray joint space narrowing (JSN) score by three radiologists. Fifteen sites at the wrist were also scored for synovitis, bone oedema and erosion using the RA MRI score.


RESULTS
Interobserver (three-reader) and intraobserver reliability (readers 1 and 2) for the cartilage score were excellent: intraclass correlations (ICC (95% CI)) 0.91, (0.86 to 0.94), 0.98 (0.96 to 1.00) and 0.94 (0.87 to 1.00), respectively. Cartilage scores (median, range) were higher in the established RA group (11.9, 2.3-27.3) than the early RA group (2.15, 0-6) (p≤0.001) but early RA scores did not differ from healthy controls (2.3, 1-8.7). Cartilage scores correlated with synovitis (R=0.52), bone oedema (R=0.63) and erosion scores (R=0.66), p<0.001 for all, and with x-ray JSN scores (R=0.68 to 0.78).


CONCLUSIONS
This MRI cartilage score demonstrated excellent reliability when tested in a three-reader system. However, cartilage loss in early RA could not be distinguished from that seen in healthy controls.
McQueen
Fiona
F
Department of Molecular Medicine and Pathology, University of Auckland, New Zealand. f.mcqueen@auckland.ac.nz
Clarke
Andrew
A
McHaffie
Alex
A
Reeves
Quentin
Q
Williams
Megan
M
Robinson
Elizabeth
E
Dong
Jing
J
Chand
Arista
A
Mulders
Desiree
D
Dalbeth
Nicola
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000473:pathology*; D001855:Bone Marrow Diseases / Q000175:diagnosis / Q000209:etiology; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000473:pathology*; D016022:Case-Control Studies; D004487:Edema / Q000175:diagnosis / Q000209:etiology; D005260:Female; D033023:Foot Joints / Q000000981:diagnostic imaging; D050823:Hand Joints / Q000000981:diagnostic imaging; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011859:Radiography; D015203:Reproducibility of Results; D013585:Synovitis / Q000175:diagnosis / Q000209:etiology; D014955:Wrist Joint / Q000473:pathology*