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).
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.
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.
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.