Background/Purpose: Rheumathoid arthritis (RA) predominantly involves finger joints. Cartilage damage promotes synovitis and has previously been shown to be predictive for bone erosions. gagCEST has recently been demonstrated to visualize biochemical alterations of cartilage in knee joints of patients following cartilage repair surgery as well as in intervertebral discs without using contrast agents. The purpose of our study was to test the feasibility of gagCEST imaging in finger joint cartilage in healthy volunteers and patients with RA to assess cartilage damage as a first step of bone destruction in RA patients.
Methods: Six healthy volunteers (mean age 33; range: 21-45 years) and four patients with ACPA and rheumatoid factor positive rheumatoid arthritis (age 58; range: 52-64 years, 2 men, 2 women, mean DAS28 4,8) were examined at a 3T MR scanner (Siemens Magnetom Trio) using two loop coils (4 cm diameter), one fixed on the palmar, the other on the dorsal side of the second metacarpophalangeal joint (MCP). For gagCEST imaging, CEST effects were prepared by a train of Gaussian RF pulses followed by signal readout with a 3D RF spoiled GRE sequence. The CEST curves were calculated for each pixel and were shifted for the water resonance to appear at 0 ppm of the Z-Spectrum. The CEST effect of the cartilage was measured with the glycosaminoglycan saturation transfer [ST = CEST (+1.3 ppm) – CEST (-1.3 ppm)/CEST (+1.3 ppm)]. Joint space width (JSW) as a morphologic feature of cartilage integrity was measured.
Results: Cartilage ST values were significantly lower in patients with seropositive rheumatoid arthritis compared to healthy volunteers (13.58 ± 6.11 vs. 27.38 ± 4.52; p=0.011). Cartilage CEST curves showed a decrease of CEST effect between 1.2 and 2.2 ppm, which corresponds to the resonance frequency of hydroxyl protons of glycosaminoglycans. There was no significant difference in JSW between healthy volunteers and RA patients.
Conclusion: gagCEST imaging revealed alterations in finger cartilage of seropositive RA patients compared to healthy controls in the absence of cartilage thinning. gagCEST is a potentially useful biomarker for imaging cartilage loss as a first step of inflammation and bone destruction in RA patients.
Disclosure:
D. P. Sewerin,
None;
D. C. Schleich,
None;
P. D. B. Ostendorf,
None;
D. S. Vordenbäumen,
None;
P. D. G. Antoch,
None;
P. D. M. Schneider,
None;
D. F. Miese,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/biochemical-mri-with-gagcest-glycosaminoglycan-chemical-exchange-saturation-transfer-imaging-of-finger-joint-cartilage-in-rheumatoid-arthritis/