Background Gout is associated with joint damage, and increased cardiovascular morbidity; it is important to diagnose and treat it. However, although clinical presentation may be strongly suggestive of gout, joint aspiration and microscopy not always yield the diagnosis. The latest technique to visualize monosodium uric acid MSU depositions and thus to diagnose gout is Dual Energy CT scan (DECT).1
Objectives To establish whether DECT is a diagnostic tool, i.e. associated with initiation or discontinuation of a urate lowering drug (ULD). Second, whether DECT results (gout deposition y/n) can be predicted by clinical and laboratory variables.
Methods Digital medical records of 147 consecutive patients with clinical suspicion of gout at the outpatient clinic of the Department of Rheumatology of Meander Medical Centre, Amersfoort, the Netherlands who underwent DECT between January 1, 2013 and December 31, 2014 were analyzed retrospectively. Collected were clinical data including medication before and after DECT, lab results, and results from diagnostic joint aspiration and DECT. The relationship between DECT results and clinica, and laboratory results was evaluated by univariate regression analyses; predictors showing a p<0.10 were entered in a multivariate logistic regression model with the DECT result as outcome variable. A manual backward stepwise technique was applied.
Results 87 patients were diagnosed with gout based on demonstration of MSU crystals in synovial fluid (SF) or positive DECT result. In 30 patients, DECT was the only conformation of gout; in 29 of them ULD was started and in 1 it was intensified. Following DECT, the current ULD was stopped in 3 patients. The clinical and laboratory variables associated with the DECT result are presented in table 1. In the multivariable regression model, cardiovascular disease y/n (OR 3.07, 95% CI 1.26–7.47), disease duration in years (OR 1.008, 95% CI 1.001–1.016), frequency of attack per year (OR 1.23, 95% CI 1.07–1.42), creatinine clearance in ml/min (OR 2.03, 95% CI 0.91–1.00) were independently associated with positive DECT results.
Conclusions DECT has impact on clinical decisions on ULD therapy. It may be a useful diagnostic imaging tool for patients who cannot undergo joint aspiration because of contraindications or with difficult to aspirate joints, or those who refuse joint aspiration.
Choi HK et al. Dual energy CT in gout: a prospectieve validation study. Ann Rheum Dis 2012; 71:1466–71.
Disclosure of Interest None declared