MRI Can Predict Cartilage Damage in Arthritis Patients

Magnetic resonance imaging scans effectively can predict cartilage damage, including osteitis- and synovitis-influenced thinning, in patients with rheumatoid arthritis at three years, according recent study results.

Researchers in New Zealand studied 28 patients with rheumatoid arthritis (RA)—15 with early-stage RA (median age, 57 years; 11 women) and 13 with late-stage RA (median age, 69 years; eight women)—and 15 healthy controls (median age, 51 years; 13 women) who completed a three-year trial. Cartilage damage, bone erosion, synovitis and osteitis were measured through 3T MRI scans. Cartilage damage from baseline parameters was predicted using a model developed by the researchers.

Status scores had a high inter-reader reliability for the Auckland MRI cartilage score (AMRICS), with an intraclass correlation coefficient (ICC) of 0.90 (95 percent CI, 0.81-0.95), while change scores had moderate AMRICS (ICC=0.58; 95 percent CI, 0.24-0.77). AMRICS score and OMERACT MRI joint space narrowing (jsn; r=0.96; P<.0001) were correlated, as well as between AMRICS score and X-ray jsn scores (r=0.80; P<.0001). Rheumatoid arthritis patients had greater AMRICS change scores than controls (P=.0672 and P=.038 for two readers).

“Using linear regression, baseline MRI cartilage, synovitis and osteitis predicted the three-year AMRICS (R2=0.67, 0.37 and 0.39, respectively),” the researchers reported. “The baseline MRI cartilage score was the most significant determinant of the three-year cartilage score with strong positive relationship (P<.0001).”

Increased cartilage scores at radiolunate and radioscaphoid joints were predicted through baseline radial osteitis (P=.0001 and P=.0012, respectively), while three-year scores also were influenced by synovitis at radioulnar (P=.001), radiocarpal (P=.04) and intercarpal-carpometacarpal joints (P=.01).

“This study has answered some questions relating to cartilage damage in rheumatoid arthritis and raised others,” the researchers concluded. “We have confirmed that measuring progression of cartilage thinning over time is possible using MRI, but our data suggest that plain radiography could be comparable in terms of separating patients from controls, when considering this endpoint alone. Longitudinal studies comparing MRI with X-ray and CT scanning are needed to further investigate this issue.”