To obtain a quantitative measure of the effect of treatment on histopathology, sections of both hind paws of all mice were scored for the severity of joint damage, extent of inflammation and bone erosion using an arbitrary scale by independent investigators 'blinded' to mouse identity.
For these reasons, earlier detection of bone erosions, using any imaging modality, would be expected to be of considerable clinical importance.
All 23 vertebral units (VU; C2 S1) were to be evaluated and scored for activity, ie, hyperintense bone marrow lesions ('bone marrow oedema') by STIR, and for erosions using the AS spine MRI-activity (ASspiMRI-a) score.
One calibrated clinician registered erosions using the Visual Erosion Dental Examination (VEDE) system.
Readers scored synovitis (0 9 for wrist joint, 0 21 for wrist plus MCP joints), bone oedema (osteitis) (0 69) and bone erosions (0 230), using the Rheumatoid Arthritis MRI Scoring (RAMRIS) system.
Images were scored by two independent, blinded readers for synovitis (0 9 wrist only (n=240), 0 21 wrist+MCP (n=223)), bone oedema (osteitis) (0 69) and bone erosions (0 230) using the OMERACT Rheumatoid Arthritis MRI Scoring system.
Serial measurements of synovitis, bone oedema (osteitis) and bone erosion were obtained using the RAMRIS system, which has demonstrated very good reliability and a high level of sensitivity to change.
When the outcome of bone erosion score was used, the strongest predictor was the baseline erosion score (R = 0.87, P <0.0001), while the baseline cartilage score was not quite as strongly predictive (R = 0.49, P = 0.01).
Despite experimental demonstrations of the efficacy of ZA for preventing bone erosion, the use of bisphosphonates in daily practice for the treatment of RA patients remains controversial.
