Dynamic contrast-enhanced MRI of the synovium and synovial subregions in knee osteoarthritis

Motivation: A precise method to quantify the degree of synovial inflammation in patients with knee osteoarthritis (OA) is needed to evaluate response to new disease modifying treatments in clinical trials. Goal(s): To evaluate the repeatability of quantitative dynamic contrast enhanced (DCE) MRI derived biomarkers for synovitis quantification in the whole synovium and synovial subregions. Approach: Test-retest study comprising DCE-MRI at baseline and 1 month follow-up in knee OA patients. Vessel mapping was used to determine synovial subregions. Results: DCE-MRI biomarkers have good test-retest repeatability in both the whole synovium and synovial subregions, with Ktrans showing the best performance. Impact: Quantitative DCE-MRI can provide precise biomarkers for synovitis quantification in knee osteoarthritis. Subregional evaluation using vessel mapping is an important tool for more precise treatment response evaluation in clinical trials with targeted local interventions, such as selective arterial embolization.