Ultrasound versus conventional radiography in the assessment of bone erosions in rheumatoid arthritis.

Bone erosions are the hallmark of joint damage in rheumatoid arthritis and both their detection and increase in number and/or in size are indicative of a poor outcome. To date, conventional radiography is still the most common imaging tool adopted for detecting and scoring joint damage in daily clinical practice, in spite of its low sensitivity with respect computerised tomography, magnetic resonance imaging or ultrasound. Ultrasound is a rapidly evolving technique that is gaining an increasing success in the assessment of patients with rheumatoid arthritis. It permits an early detection and careful characterisation of bone erosions playing a key role in both diagnostic and therapeutic procedures. Ultrasound presents several advantages over other imaging techniques: it is patient-friendly, safe and non-invasive, free of ionising radiation, less expensive, and permit multiple target assessment in real time without the need for external referral. The aim of this review is to compare conventional radiography and ultrasound in the assessment of bone erosions in RA in daily rheumatology practice and to provide insights into which modality can provide the optimal information for a desired outcome in a given clinical trial or practice situation.