Bone erosions in patients with chronic gouty arthropathy are associated with tophi but not bone oedema or synovitis: new insights from a 3 T MRI study.
OBJECTIVE
Bone erosion has been linked with tophus deposition in gout but the roles of osteitis (MRI bone oedema) and synovitis remain uncertain. Our aims in this prospective 3 T MRI study were to investigate the frequency of these features in gout and determine their relation to one another.


METHODS
3 T MRI scans of the wrist were obtained in 40 gout patients. Scans were scored independently by two radiologists for bone oedema, erosions, tophi and synovitis. Dual-energy CT (DECT) scans were scored for tophi in a subgroup of 10 patients.


RESULTS
Interreader reliability was high for erosions and tophi [intraclass correlation coefficients (ICCs) 0.77 (95% CI 0.71, 0.87) and 0.71 (95% CI 0.52, 0.83)] and moderate for bone oedema [ICC = 0.60 (95% CI 0.36, 0.77)]. Compared with DECT, MRI had a specificity of 0.98 (95% CI 0.93, 0.99) and sensitivity of 0.63 (95% CI 0.48, 0.76) for tophi. Erosions were detected in 63% of patients and were strongly associated with tophi [odds ratio (OR) = 13.0 (95% CI 1.5, 113)]. In contrast, no association was found between erosions and bone oedema. Using concordant data, bone oedema was scored at 6/548 (1%) sites in 5/40 patients (12.5%) and was very mild (median carpal score = 1, maximum = 45). In logistic regression analysis across all joints nested within individuals, tophus, but not synovitis, was independently associated with erosion [OR = 156.5 (21.2, >999.9), P < 0.0001].


CONCLUSIONS
Erosions were strongly associated with tophi but not bone oedema or synovitis. MRI bone oedema was relatively uncommon and low grade. These findings highlight the unique nature of the osteopathology of gout.
Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Rd, Grafton, Auckland 1023, New Zealand. f.mcqueen@auckland.ac.nz.
Fiona M
FM
McQueen
Anthony
A
Doyle
Quentin
Q
Reeves
Angela
A
Gao
Amy
A
Tsai
Greg D
GD
Gamble
Barbara
B
Curteis
Megan
M
Williams
Nicola
N
Dalbeth
D000328:Adult; D000368:Aged; D015210:Arthritis, Gouty / Q000150:complications / Q000175:diagnosis*; D004487:Edema / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D013585:Synovitis / Q000175:diagnosis / Q000209:etiology*; D014057:Tomography, X-Ray Computed; D014955:Wrist Joint / Q000000981:diagnostic imaging / Q000473:pathology*
DECT; MRI; bone oedema; gout; tophi