Magnetic resonance imaging of the spine and the sacroiliac joints in ankylosing spondylitis and undifferentiated spondyloarthritis during treatment with etanercept.

OBJECTIVE To assess the changes in inflammatory lesions of the spine and the sacroiliac (SI) joints as detected by magnetic resonance imaging (MRI) in patients with ankylosing spondylitis (AS) and undifferentiated spondyloarthritis (uSpA) with predominant axial symptoms during treatment with etanercept. METHODS MRI of the spine and/or the SI joints of patients with active AS or axial uSpA was performed at baseline (TP0, n = 25), after 6 weeks (TP1, n = 20), and after 24 weeks of continuous treatment with etanercept (TP2, n = 12). T1 weighted spin echo pre -(T1), post-gadolinium (T1/Gd-DTPA) and short tau inversion recovery (STIR) MRI sequences were used to assess chronic and active spinal lesions using the scoring system ASspiMRI. Active and chronic SI lesions were assessed using a simple scoring system. RESULTS By use of the definite STIR sequence, significant regression of spinal inflammation was already seen already after 6 weeks in the patients treated with etanercept (mean (SD) 11.2 (13.8) at TP0 v 6.8 (7.9) at TP1; p = 0.023) but not in patients treated with placebo. Continuous treatment with etanercept for 24 weeks reduced active spinal changes by 69% (p = 0.012). T1/Gd-DTPA sequences gave similar results. There was only a trend for a decrease of active inflammatory lesions of the SI joints. CONCLUSIONS Etanercept treatment in patients with active AS and uSpA leads to regression of active inflammatory lesions of the spine as depicted by MRI. The potential role of etanercept on deceleration of chronic spinal changes needs further study.