Predictive Value of Magnetic Resonance Imaging in Patients With Juvenile Idiopathic Arthritis in Clinical Remission.

objectiveTo define the prevalence of subclinical synovitis on magnetic resonance imaging (MRI) in a large cohort of patients with juvenile idiopathic arthritis (JIA) in clinical remission and to evaluate its predictive value in terms of disease flare and joint deterioration.

methodsNinety patients with clinically inactive JIA who underwent a contrast-enhanced (CE)-MRI of a previously affected joint were retrospectively included. Each joint was evaluated for synovitis, tenosynovitis, and bone marrow edema. Baseline and follow-up radiographs were assessed to evaluate structural damage progression.

resultsCE-MRI was acquired in 45 wrists, 30 hips, 13 ankles, and 2 knees. Subclinical synovitis was detected in 59 (65.5%) of 90 patients and bone marrow edema in 42 (46.7%) of 90 patients. Fifty-seven of 90 (63.3%) patients experienced a disease flare during follow-up. Forty-four of 59 (74.6%) patients with subclinical synovitis experienced a disease flare versus 13 (41.9%) of 31 patients with no residual synovitis on MRI (P = 0.002). The presence of subclinical synovitis was the best predictor of disease flare on multivariable regression analysis (hazard ratio [HR] 2.45, P = 0.003). Baseline and follow-up radiographs were available for 54 patients, and 17 (31.5%) of 54 patients experienced radiographic damage progression. The presence of bone marrow edema (HR 4.40, P = 0.045) and being >17 years old (HR 3.51, P = 0.04) were strong predictors of joint damage progression in the multivariable analysis.

conclusionMRI-detected subclinical inflammation was present in a large proportion of patients with JIA despite clinical remission. Subclinical synovitis and bone marrow edema have been shown to play a role in predicting the risk of disease relapse and joint deterioration, with potential implications for patients' management of the disease.