J Rheum Dis.  2011 Jun;18(2):137-141.

Dual-Energy CT as a New Diagnostic Tool for Gout

• Lee CH
• Lee MS
• Ahn SH
• Lee YM
• Kim HJ
• Song JH
• Juhng SK

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.

Keyword

Gout; Dual-Energy CT; Noninvasive

MeSH Terms

Arthritis, Infectious
Cellulitis
Chondrocalcinosis
Clinical Coding
Gout
Humans
Hydrazines
Hyperuricemia
Incidence
Joints
Metatarsophalangeal Joint
Microscopy, Polarization
Middle Aged
Organothiophosphorus Compounds
Uric Acid
Hydrazines
Organothiophosphorus Compounds
Uric Acid

Figure

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  Figure 1. The images visualize multiple tophi around the proximal interphalangeal joints of the right hand and the 1 st metatarsophalang-eal joint of the left foot.

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  Figure 2. The dual energy computed tomography images demons-trate uric acid deposits (green color) on multiple joints of the right hand and both feet.

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  Figure 3. Repolarizing microscopy of the aspirated fluid from the left knee shows negative birefringent needle-shaped crystals, indica-ting monosodium urate crystals.

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  Figure 4. The dual energy computed tomography images demonst-rate uric acid deposits (green color) on the posterior cruciate ligament of the left knee.

Reference

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