Role of Dual Energy Computed Tomography Imaging in the Diagnosis of Gout

Abstract

Gout is a well-known inflammatory arthritis and affects four percent of the United States population. It results from the deposition of uric acid crystals in joints, tendons, bursae, and other surrounding tissues. Prevalence of gout has increased in the recent decade. Gout is usually seen in conjunction with other chronic comorbid conditions like cardiac disease, metabolic syndrome, and renal disease. The diagnosis of this inflammatory arthritis is confirmed by visualization of monosodium urate (MSU) crystals in the synovial fluid. Though synovial fluid aspiration is the standard of care, it is often deferred because of inaccessibility of small joints, patient assessment during intercritical period, or procedural inexperience in a primary care office. Dual energy computed tomography (DECT) is a relatively new imaging modality which shows great promise in the diagnosis of gout. It is a good noninvasive alternative to synovial fluid aspiration. DECT is increasingly useful in diagnosing cases of gout where synovial fluid fails to demonstrate monosodium urate crystals. In this article, we will review the mechanism, types, advantages, and disadvantages of DECT.

Keywords: dect; dual energy ct; gout; monosodium urate crystals.

Figure 1. 3D DECT reconstruction images

Image showing a patient with tophaceous gout previous to (a) and 16 months after treatment with febuxostat (b). Image 1b shows complete resolution of the tophi (areas of green pixels around the nails represent typical artifacts); Purple: calcium; Green: MSU deposits; A: anterior (Reproduced with permission from journal-Gout and Hyperuricemia).

Figure 2. DECT multiplanar reformation (MPR)

Images revealing multiple MSU tophi formations (in green) in the first left metatarsophalangeal joint (2a), in front of the right tibia (2b) and around the right medial cuneiform (2c). Smaller lesions were also seen in the right 1st and 4th metatarsophalangeal joints (2a). (Reproduced with permission from SOMATOM Sessions and X-LEME Diagnóstico por Imagem, Curitiba, Brazil).