Assessment of synovitis with contrast-enhanced MRI using a whole-joint semiquantitative scoring system in people with, or at high risk of, knee osteoarthritis: the MOST study

Abstract

Objectives To introduce a comprehensive and reliable scoring system for the assessment of whole-knee joint synovitis based on contrast-enhanced (CE) MRI. Methods Multicenter Osteoarthritis Study (MOST) is a cohort study of people with, or at high risk of, knee osteoarthritis (OA). Subjects are an unselected subset of MOST who volunteered for CE-MRI. Synovitis was assessed at 11 sites of the joint. Synovial thickness was scored semiquantitatively: grade 0 (<2 mm), grade 1 (2–4 mm) and grade 2 (>4 mm) at each site. Two musculoskeletal radiologists performed the readings and inter- and intrareader reliability was evaluated. Whole-knee synovitis was assessed by summing the scores from all sites. The association of Western Ontario and McMaster Osteoarthritis Index pain score with this summed score and with the maximum synovitis grade for each site was assessed. Results 400 subjects were included (mean age 58.8±7.0 years, body mass index 29.5±4.9 kg/m2, 46% women). For individual sites, intrareader reliability (weighted κ) was 0.67–1.00 for reader 1 and 0.60–1.00 for reader 2. Inter-reader agreement (κ) was 0.67–0.92. For the summed synovitis scores, intrareader reliability (intraclass correlation coefficient (ICC)) was 0.98 and 0.96 for each reader and inter-reader agreement (ICC) was 0.94. Moderate to severe synovitis in the parapatellar subregion was associated with the higher maximum pain score (adjusted OR (95% CI), 2.8 (1.4 to 5.4) and 3.1 (1.2 to 7.9), respectively). Conclusions A comprehensive semiquantitative scoring system for the assessment of whole-knee synovitis is proposed. It is reliable and identifies knees with pain, and thus is a potentially powerful tool for synovitis assessment in epidemiological OA studies.

Can Structural Joint Damage Measured with MR Imaging Be Used to Predict Knee Replacement in the Following Year?

“…Whether aggressive treatment of inflammation reduces the risk for knee replacement will have to be shown in subsequent randomized studies. We acknowledge that assessment of Hoffa signal intensity changes as a surrogate for synovitis is an inferior measure when compared with contrast material-enhanced imaging, especially owing to its nonspecificity (30,31).…”

Evolution of synovitis in osteoarthritic knees and its association with clinical features

“…The total synovitis score of 11 sites was calculated (range 0e22). A total score of 0e4 was considered normal (no synovitis); 5e8 represents a mild, 9e12 a moderate and above 13 a severe synovitis 13 . Intra-class correlation (ICC) was based on a random sample of 15% Gd-chelate enhanced MR images and was 0.93 for synovitis and 0.90 for synovitis change.…”

“…As synovitis is known to be patchy and heterogeneous 11 , a synovitis scoring method on magnetic resonance imaging (MRI) should encompass a sufficient number of compartments. The synovitis scoring method developed by Guermazi et al 13 is a comprehensible and practical method, which meets these requirements and compares well with synovial inflammation in tissue biopsies of knee OA patients 8 .…”

The impact of MRI on the clinical management of inflammatory arthritides

“…A recent report showed that synovitis detected by contrast-enhanced MRI had a strong association (adjusted odds ratio 9.2) with at least moderate severity of knee pain as assessed by the Western Ontario and McMaster Osteoarthritis Index pain scale [169]. A comprehensive whole-knee joint synovitis scoring system has been proposed recently, which showed a high reliability based on contrast-enhanced MRI [170]. Interventional studies assessing intraarticular corticosteroids or NSAIDs and paracetamol demonstrated associations between decreased synovitis and reduction of pain in patients with knee OA [171,172].…”