Clinical utility of dual energy CT in gout

Gout is characterized by urate deposition and is associated with joint damage and with cardiovascular morbidity. Early diagnosis, treatment and screening for cardiovascular morbidity are important. Dual-Energy-CT (DECT) is a new imaging technique without contrast fluid to detect gout. In Part I of this thesis we conclude that DECT has additive value in gout classification, especially if the investigation of urate crystals in the joint fluid is not possible or negative. Negative results can be false-negative, due to a sampling error (incorrect placement of the needle in the joint, or urate deposition outside the joint, for example on tendons around the joint) or due to an incorrect technique of testing urate crystals in the joint fluid. In patients with a short duration of joint symptoms, the value of DECT appears to be less, but is not negligible. As 93% of patients had urate deposition in ankles/feet, we suggest that scanning of these regions, together with the index joint, could be a well-balanced cost-effective choice.
Part II of this thesis confirms and specifies the association of gout with cardiovascular comorbidity. At the time of the gout diagnosis, urate deposits on DECT are already associated with a history of symptomatic cardiovascular disease. In addition, two-thirds of newly diagnosed gout patients already had a (very) high cardiovascular risk. Presence of gout should encourage doctors to screen for cardiovascular risk factors, and to treat if necessary. Our advice is to include gout in cardiovascular risk scores.