From the Guidelines
Gouty arthritis can be seen on X-rays, but only in chronic or late stages of the disease, as radiographs are not useful in confirming the diagnosis of early or acute gout. According to the EULAR evidence-based recommendations for gout diagnosis, radiographs may show typical features in chronic gout, but are not useful in early diagnosis 1. The study suggests that radiographic changes, such as asymmetrical swelling and subcortical cysts without erosion, may be useful to differentiate chronic gout from other joint conditions, with a likelihood ratio of 4.13 and 6.39, respectively 1. Some key features that may be visible on X-rays in chronic gout include:
- Punched-out erosions with overhanging edges
- Preservation of joint space until late stages
- Soft tissue swelling These changes often appear after years of recurrent gout attacks, particularly in commonly affected areas like the first metatarsophalangeal joint, ankles, knees, and hands 1. While X-rays can help diagnose chronic gout, they are less useful for early disease detection, and other imaging techniques like ultrasound, CT, or dual-energy CT may show changes earlier and more specifically 1. The definitive diagnosis of gout still relies on identifying monosodium urate crystals in joint fluid under polarized microscopy, as imaging findings alone are not always specific to gout 1.
From the Research
Gouty Arthritis and X-ray Visibility
- Gouty arthritis can be seen in X-ray, but its utility is limited to late stages of the disease 2.
- Radiography demonstrates erosions in late stages of gout, but it has a low utility in early diagnosis 2, 3.
- X-ray findings of gouty arthropathy include osseous erosions and tophi, which may involve periarticular tissues, tendons, and bursae 4.
- However, other imaging techniques such as ultrasound, dual-energy computed tomography, and magnetic resonance imaging are more sensitive and specific for diagnosing gout 2, 4, 3.
Imaging Techniques for Gout Diagnosis
- Ultrasound has a high overall sensitivity in diagnosing gout, with the 'double contour' sign having a high specificity 2.
- Dual-energy computed tomography (DECT) can detect monosodium urate crystals burden with high accuracy, but its use is limited due to radiation exposure and cost 2, 3.
- Magnetic resonance imaging is good at detecting tophi, bone marrow oedema, and erosions, but its role in diagnosis is limited due to high cost and limited availability 2, 4.