title: The responsiveness of novel, dynamic, contrast-enhanced magnetic resonance measures of total knee synovitis after intra-articular corticosteroid for painful osteoarthritis.
abstract: OBJECTIVE
  Sensitive biomarkers are needed to understand synovial response to therapy in osteoarthritis (OA). Dynamic, contrast-enhanced magnetic resonance imaging (DCE MRI) provides quantitative, novel measures of synovial inflammation. This exploratory study examined DCE-assessed synovial response to intra-articular corticosteroid (IACS).
  
  
  METHODS
  People with ACR clinical criteria OA knee underwent 3 T MRI pre- and 2 weeks post-IACS. Five MRI variables were assessed blindly: total synovial volume (semi-automated computer program), early enhancement rate (EER) and late enhancement ratio of the entire knee, synovial volume × late enhancement and a semi-quantitative (SQ) score (six sites scored 0-3). Clinical symptoms were assessed using pain visual analogue score (VAS) and WOMAC.
  
  
  RESULTS
  13 participants (5 male, mean age 63, mean pain VAS 66 mm mean body mass index (BMI) 31.3 kg/m(2)) were included. The majority of MRIs demonstrated no change in SQ score although the DCE variables changed to some extent in all. There was generally a reduction in synovial volume ((Wilcoxon test) median (interquartile range (IQR)) reduction 14 cm(3) (-1, 29)), EER (0.2% (-0.3, 0.6)) and late enhancement ratio (8% (-0.5, 41)). Synovial volume × late enhancement ratio demonstrated a substantive reduction (2250 (-930, 5630)) as well as the largest effect size, r = 0.45. There was a median 26% reduction in EER in participants with good symptomatic response to IACS, contrasting with a 23% increase in those who responded poorly.
  
  
  CONCLUSIONS
  DCE MRI may be more sensitive than a SQ score at detecting post-therapy synovial changes. The association between EER and symptomatic response to IACS may reflect a closer relation of this biomarker to synovial inflammation than with volumetric assessment.
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, UK; NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK. Electronic address: c.y.j.wenham@leeds.ac.uk.
authors.forename: C Y J
authors.initials: CY
authors.lastname: Wenham
authors.affiliation: NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK.
authors.forename: S
authors.initials: S
authors.lastname: Balamoody
authors.affiliation: NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Grainger
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, UK; NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK.
authors.forename: E M A
authors.initials: EM
authors.lastname: Hensor
authors.affiliation: Leeds Teaching Hospitals NHS Trust, Leeds, UK.
authors.forename: S
authors.initials: S
authors.lastname: Draycott
authors.affiliation: NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK.
authors.forename: R
authors.initials: R
authors.lastname: Hodgson
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, UK; NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK.
authors.forename: P G
authors.initials: PG
authors.lastname: Conaghan
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use*; D000368:Aged; D018771:Arthralgia / Q000188:drug therapy* / Q000209:etiology; D003287:Contrast Media; D005260:Female; D006801:Humans; D007270:Injections, Intra-Articular; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications / Q000188:drug therapy / Q000473:pathology*; D013585:Synovitis / Q000188:drug therapy / Q000209:etiology / Q000473:pathology*; D016896:Treatment Outcome
chemical_list: D000305:Adrenal Cortex Hormones; D003287:Contrast Media
keywords: Biomarker; Dynamic magnetic resonance imaging; Intra-articular corticosteroid; Knee; Osteoarthritis; Synovium