Objective: To compare ultrasonography (US) and magnetic resonance imaging (MRI) in their capability to detect bone erosions in early-advanced rheumatoid arthritis, where no erosion was evident on conventional radiography (X-ray).
Methods: Metacarpophalangeal (MCP), radiocarpal and ulnocarpal joints of 13 patients with rheumatoid arthritis, with bone erosion that was not detected by conventional X-ray, were examined by US and MRI. Ten controls underwent examination of the same joints by US.
Results: None of the controls showed bone erosions at US examination. No significant difference between US and MRI in detecting bone erosion was observed in wrist joints, whereas a significantly higher number of erosions was detected by US in MCP joints.
Conclusion: US is at least as sensitive as MRI in detecting bone erosions in MCP and wrist joints. Since US examination is a more easily available and less expensive procedure than MRI, our findings justify its use as a diagnostic tool for early arthritis. In addition US may also be utilized in the follow up of patients with an established diagnosis of inflammatory arthritis.