THE MRI PATTERN OF WRIST ARTHRITIS IS SIMILAR IN GOUT AND RHEUMATOID ARTHRITIS

1. [SAT0409]   THE MRI PATTERN OF WRIST ARTHRITIS IS SIMILAR IN GOUT AND RHEUMATOID ARTHRITIS

G. Zampogna*¹, M. Parodi¹, F. Paparo², R. Andracco¹, G. Ferrero², G. Garlaschi², M. A. Cimmino<sup>1

1</sup>Clinica Reumatologica, Dipartimento di Medicina Interna, 2Sezione di Diagnostica per Immagini, Dipartimento di Medicina Interna, Università di Genova, Genova, Italy

Background: Little is known on the MRI pattern of gouty arthritis (GA), the majority of studies having been focused on the characterization of tophi.

Objectives: To evaluate the MRI pattern of acute GA of the wrist; to compare it with rheumatoid arthritis (RA).

Methods: 7 patients (6 men, median age 75 yrs) affected by GA, diagnosed by ACR criteria and demonstration of MSU crystals in tophi or synovial fluid, were studied. 7 patients (4 men, median age 64 yrs) affected by active RA, diagnosed according to the ACR criteria and eligible for rituximab treatment, were also considered. MRI was performed on an extremity-dedicated machine (Artoscan C, Esaote, Italy) using pre and post contrast T1 weighted Turbo 3D, and coronal and axial STIR sequences. The RA MRI Scoring system (RAMRIS) was used for the evaluation of synovitis, bone oedema, and erosions. Because the RAMRIS score for synovitis could not be evaluated in 3 patients without contrast agent injection because of renal insufficiency, an additional score based on STIR sequences (grade 0 = thin hyperintense signal in the RAMRIS areas, grades 1, 2 and 3 = involvement <33%, 34-66%, or >67%) was included.

Results: Patients with gout had a mean disease duration of 15.8 years; poliarticular involvement was present in all but one. Wrist involvement was a new location of GA in 4 patients, lasting less than 2 months at the time of MRI. Synovitis, bone oedema, and erosions were seen in all patients with GA and RA. Comparison between patients with gout and RA is shown in table 1.

Table:

Conclusion: An unexpected high frequency of synovitis, bone oedema and erosions was seen in patients with acute GA of the wrist. The MRI pattern was severe and comparable, except for erosions, to that observed in RA patients with particularly active disease, needing a second-line biologic agent. As a consequence, RA and GA cannot be differentiated by MRI. Bone lesions, including erosions, occurred also in subjects who did not recall previous involvement of the affected wrists. This observation may indicate a possible subclinical activity of gout. Bone oedema is present in GA and is probably a very rapid response to inflammation, being visualized after few days from the onset. Acute GA may be a useful model to study the MRI findings associated with arthritis, because the time of onset of acute inflammation can be easily determined and the attack is rapidly and completely aborted by the use of colchicine or NSAIDs.

Disclosure of Interest: none declared.