Toappreciate the implication of Dual energy CT (DECT) in diagnosis of Gout, a highly accurate noninvasive imaging tool, and to show case examples of patients imaged with this technique.

Gout is a common crystalline arthropathy of metabolic origin, triggered by crystallization of Monosodium urate (MSU) within the joints(1). A definitive diagnosis of gout is based upon the identification of monosodium urate crystals in synovial fluid or a tophus, which demonstrate a needle-like morphology and strong negative birefringence. Nonetheless, in clinical practice, only 11% of patients undergo arthrocentesis and the vast majority of cases of gout are diagnosed on clinical grounds (2). Up to 42% of patients with gout have normal serum uric acid levels....

DECT can accurately characterise MSU deposition and improve clinical diagnosis of unclear arthropathies (5). The dual source scanner is equipped with two x-ray tubes and allows simultaneous acquisition at two different energy levels (80 and 140 kVp) and subsequent creation of two different datasets that are loaded into the post processing software on a Multi technique CT workstation. A material decomposition algorithm is then able to differentiate the soft tissue material based on its chemical composition. This allows accurate and specific characterisation of MSU deposition...

DECT provides a noninvasive imaging modality for: Diagnosing gout by demonstrating uric acid deposition. Differentiating gout from other infalmmatory arthropathies. Quantifying and depicting distribution of MSU in multiple joints. Monitoring disease progression or response to therapy. Potentially reducing the burden of chronic complications associated with gout and possibly obviating asthrocentesis. limited abvailability will likey confine the role of DECT to those individuals with diagnostic uncertainty and access to larger imaging centers.

1. Lawrence RC, Felson DT, Helmic CG et al (2008) Estimates of the prevalence of arthritis and other rheumatic conditions in the United States. Part II. Arthritis rheum 58:26-35 2. Underwood M (2006) Diagnosis and managemet of gout . BMJ 332: 1315-1319 3. Schlesinger N, Baker DG, Schumacher HR Jr. Serum urate during bouts of acute gouty arthritis. J Rheumatol.1997:325-341 4. Brower AC, Flemming DJ. Gout. In: Arthritis: In Black and White. 2nd ed. Philadelphia, Pa: WB Saunders;1997:325-341 5. Thiele RG, Schlesinger N (2007) Diagnosis...