Dual-Energy CT as a New Diagnostic Tool for Gout

ABSTRACT

Gout is the most common crystal-associated arthropathy. Gout is caused by deposition of monosodium urate crystals within the joints, and it is often associated with hyperuricemia. Acute gout involves the first metatarsophalangeal joint (podagra) in approximately 50% of cases and its peak incidence occurs in middle age. Although the clinical features can help with making the diagnosis of gout, many inflammatory diseases such as cellulitis, pseudogout and septic arthritis can mimic or coexist with it. The definitive diagnosis requires polarized light microscopy of the fluid aspirated from the involved joint and this shows needle-shaped, negative birefringent monosodium urate crystals. However, joint aspiration can be technically difficult, and none of the conventional imaging modalities for gout specifically identifies the chemical composition of uric acid. The advent of Dual-Energy CT (DECT) is a noninvasive method that has the potential to confirm gout and monitor the response to treatment. DECT scan can show monosodium urate deposition by using color coding. The authors performed DECT scans for detecting uric acid deposition and confirming the gout noninvasively.