Objectives: To investigate intra-and intermodality agreements of CT and MRI erosion volumes in RA metacarpophalangeal (MCP) joints, and to compare the volumes with erosion scores for CT, MRI and radiography.
Methods: Seventeen RA-patients and four healthy controls underwent unilateral CT, MRI and radiography of one hand’s 2nd-5th MCP-joints. Erosion volumes (using OSIRIS software) and scores were determined from radiography (only scores), CT and MRI.
Results: CT, MRI and radiography detected 77, 62 and 12 erosions, respectively. On CT, the mean erosion volume was 26 (median 10; range 0-248) mm3, while 30 (18; 1-163) mm3 on MRI. Total erosion volumes (per patient/control) were 97 (29; 0-485) mm3 on CT and 90 (46; 0-389) mm3 on MRI. For volumes, Spearman’s correlation coefficients were 0.96-0.99 (CT vs. CT), 0.95-0.98 (MRI vs. MRI) and 0.64-0.89 (CT vs. MRI), all p<0.01. MRI erosion volumes correlated with OMERACT-RAMRIS erosion scores 0.91-0.99 (p<0.01) and the Sharp/van der Heijde erosion score (0.49-0.63; p<0.01).
Conclusion: Very high intramodality and high intermodality agreements of CT and MRI erosion volumes were demonstrated, encouraging further testing in longitudinal studies. A close correlation with CT and MRI erosion volumes supports the OMERACT-RAMRIS erosion score as being a valid measure of RA joint destruction.
- bone erosions
- computed tomography
- magnetic resonance imaging
- rheumatoid arthritis