Diagnostic quality and scoring of synovitis, tenosynovitis and erosions in low-field MRI of patients with rheumatoid arthritis: a comparison with conventional MRI.
OBJECTIVE
To compare dedicated low-field MRI (lfMRI) with conventional MRI (cMRI) in the detection and scoring of synovitis, tenosynovitis and erosions in patients with rheumatoid arthritis.


METHODS
The wrist and finger joints of 17 patients with rheumatoid arthritis (median (range) disease duration 8 years (7-12); Disease Activity Score 3.3 (2.6-4.5)) were examined by 0.2 T lfMRI and 1.5 TcMRI. The protocols comprised coronal spin-echo and three-dimensional gradient-echo sequences before and after contrast medium administration. Synovitis of the metacarpophalangeal and proximal interphalangeal joints 2-5 and the wrist joints was scored according to Outcome Measures in Rheumatology recommendations. Tenosynovitis and erosions were scored using 4-point and 6-point scales, respectively. The results were analysed by calculating kappa values and performing McNemar's test intra-individually on a joint-by-joint basis.


RESULTS
Agreement between the two MRI techniques was good to excellent for synovitis and erosions, and moderate for tenosynovitis. Of the 306 joints evaluated, 245 and 200 joints showed synovitis in lfMRI and cMRI, respectively. Scoring of synovitis of the finger joints yielded kappa values from 0.69 to 0.94. Of the 68 flexor tendons evaluated, tenosynovitis was diagnosed by lfMRI in 24 and by cMRI in 33 instances. Of the 391 bones evaluated, 154 and 139 showed erosions in lfMRI and cMRI, respectively. kappa values for erosion scores were between 0.65 and 1.


CONCLUSIONS
Dedicated, lfMRI shows high agreement with cMRI in diagnosing and scoring synovitis, tenosynovitis and erosions in rheumatoid arthritis when using standardised scoring systems.
Schirmer
Claudia
C
Department of Radiology, Charité Medical School, Campus Mitte, Charitéplatz 1, 10117 Berlin, Germany.
Scheel
Alexander K
AK
Althoff
Christian E
CE
Schink
Tania
T
Eshed
Iris
I
Lembcke
Alexander
A
Burmester
Gerd-Rüdiger
GR
Backhaus
Marina
M
Hamm
Bernd
B
Hermann
Kay-Geert A
KG
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications* / Q000473:pathology; D003287:Contrast Media; D003430:Cross-Sectional Studies; D005260:Female; D005384:Finger Joint / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013585:Synovitis / Q000175:diagnosis* / Q000209:etiology; D013717:Tenosynovitis / Q000175:diagnosis* / Q000209:etiology; D014955:Wrist Joint / Q000473:pathology
D003287:Contrast Media