SAT0213 Determination of bone erosions in patients with arthritis by ultrasonography, mri and conventional radiography

Abstract

Background Conventional radiography (CR) is the standard of reference for detection and quantification of destruction in arthritis. However several studies1,2 have shown that Magnetic Resonance Imaging (MRI) may be superior to CR in the detection of bone erosion while the use of ultrasonography (US) has not yet been fully clarified. Objectives To compare CR with US and MRI in detecting bone erosions in patients with arthritis. Methods 16 patients (9 women and 7 men, median age 50,5 years, range (31–69)) with arthritis were included and examined by CR in 2 planes with Norgaard views, US with a 15 MHz linear transducer in longitudinal scans consecutively covering the whole joint and by 1,5 T MRI with T1-weighted images. Only wrist, 2nd and 3rd MCP joints were evaluated. A total of 106 bone surfaces in the hands were examined by US (45 joints) and 112 bone surfaces by MRI and CR (48 joints). Each imaging modality was evaluated independently. Erosions in CR were evaluated on a standardised sheath. An US erosion were defined as a defect in the bone cortex visualised in the longitudinal scan and different from known US bone irregularities due to tendon tracks etc. A MRI erosion was defined as a focal loss of signal intensity within the bone. For all imaging modalities the erosions were marked ± erosion in the bone surface examined. Results US detected a total of 36 bone surfaces with erosions, MRI 29 and CR 7. US and MRI agreed on 76 of 106 surfaces (72%), Kappa = 0,33; US and CR agreed on 74 of 106 surfaces (70%), Kappa 0,14 and MRI and CR agreed on 86 of 112 surfaces (77%), Kappa 0,24. Conclusion Of the three imaging modalities US and MRI were in closest agreement and both more sensitive than CR. Differences in the US and MRI interpretations of erosions remain to be clarified. References Klarlund M, et al. Magnetic resonance imaging, radiography and scintigraphy of the finger joints: one year follow up of patients with early arthritis. Ann Rheum Dis 2000;59:521–8 Backhaus M, et al. Arthritis of the finger joints. Arthritis Rheum. 1999;42:1232–45