MacKay J, Watkins L, Gold G, et al. - This study was intended to use hybrid positron emission tomography-magnetic resonance imaging (PET-MRI) to ascertain if synovitis adjacent to peripheral bone subregions with increased metabolic activity is greater than adjacent to regions without increased metabolic activity and explore the relationship between subregional bone metabolic activity and adjacent synovitis. Researchers enrolled 11 participants (22 knees) with a diagnosis of osteoarthritis in at least one knee. They conducted simultaneous bilateral knee PET-MRI. Although there is some overlap, synovitis is more intense adjacent to peripheral bone regions with increased metabolic activity than those without. It was shown that subregional bone metabolic activity is positively correlated with the intensity of adjacent synovitis.