Glycosaminoglycan chemical exchange saturation transfer of lumbar intervertebral discs in patients with spondyloarthritis.

PURPOSE: To assess glycosaminoglycan (GAG) content of lumbar intervertebral discs (IVD) in patients with spondyloarthritis (SpA) using glycosaminoglycan chemical exchange saturation transfer (gagCEST). MATERIALS AND METHODS: Ninety lumbar intervertebral discs of nine patients with SpA and nine age-matched healthy controls (eight patients with ankylosing spondylitis; one patient with spondylitis related to inflammatory bowel disease; mean age: 44.1 ± 14.0 years; range: 27-72 years) were examined with a 3T magnetic resonance imaging (MRI) scanner in this prospective study. The MRI protocol included standard morphological, sagittal T2 -weighted (T2 w) images to assess Pfirrmann score of the five lumbar IVDs (L1 to S1) and biochemical imaging with gagCEST to calculate a region of interest analysis of nucleus pulposus (NP) and annulus fibrosus (AF). Prior to statistical testing of gagCEST effects (MTRasym values in percent) in patients and controls, IVDs were classified according to the Pfirrmann score. RESULTS: Significantly lower gagCEST values of NP and AF were found in SpA patients compared with healthy volunteers (NP: 1.41% ± 0.41%, P = 0.001; 95% confidence interval, CI [0.600%-2.226%]; AF: 1.19% ± 0.32%, P < 0.001; CI [0.560%-1.822%]) by comparing the differences of the means. Pooled nondegenerative IVDs (Pfirrmann 1 and 2) had significantly lower gagCEST effects in patients suffering from SpA compared with healthy controls in NP (P < 0.001; CI [1.176%-2.337%]) and AF (P < 0.001; CI [0.858%-1.779%]). No significant difference of MTRasym values was found in degenerative IVDs between patients and controls in NP (P = 0.204; CI [-0.504%-2.170%]). CONCLUSION: GagCEST analysis of morphologically nondegenerative IVDs (Pfirrmann score 1 and 2) in T2 w images demonstrated significantly lower GAG values in patients with spondyloarthritis in NP and AF, possibly representing a depletion of GAG in spondyloarthritis in the absence of morphologic degeneration.

Rheumatoid Arthritis Magnetic Resonance Imaging Score Predicts Therapy Response: Results of the German ArthroMark Cohort.

OBJECTIVE: Markers for treatment response in rheumatoid arthritis (RA) are lacking. The aim of the study was to assess the performance of the RA magnetic resonance imaging (MRI) scoring system (RAMRIS) in combination with serum biomarkers to predict response to methotrexate (MTX) treatment in therapy-naive patients with early RA by using high-field MRI. METHODS: Twenty-eight patients with RA were prospectively assessed with baseline 3-T MRI of the clinical dominant hand, 3 and 6 months after MTX. The patients met the 2010 American College of Rheumatology/European League Against Rheumatism (EULAR) criteria [average age 56.8 yrs (range 39-74); positive for rheumatoid factor and/or anticyclic citrullinated peptide antibodies; disease duration < 6 mos (range 2-23 weeks)]. RAMRIS and serum biomarkers consisting of various experimental proteins including receptor activator of nuclear factor-κB ligand (RANKL) were obtained. Remission or treatment response was defined according to EULAR. To adjust for intrapersonal correlation, generalized linear mixed models were used. RESULTS: Treatment response at 3 months was associated to low RAMRIS erosion subscores and low total RAMRIS scores (p = 0.019 and 0.03, respectively). Remission at 6 months was associated to low RANKL levels (p = 0.033). In multivariate analyses, response at 3 and 6 months was predicted more accurately with the inclusion of total RAMRIS score, RAMRIS synovitis subscore at the second metacarpophalangeal (MCP) joint, or a combination of the two (p value likelihood ratio test = 0.035, 0.035, and 0.041, respectively). Remission was more accurately predicted with inclusion of RANKL, with no significant predictive effect of MRI. CONCLUSION: Baseline total RAMRIS can predict EULAR response. RAMRIS synovitis subscore at the second MCP joint and RANKL are associated with response and remission, respectively.