title: Synovitis assessed on static and dynamic contrast-enhanced magnetic resonance imaging and its association with pain in knee osteoarthritis: A cross-sectional study.
abstract: OBJECTIVE
  To investigate the association between pain and peripatellar-synovitis on static and dynamic contrast-enhanced MRI in knee osteoarthritis.
  
  
  METHODS
  In a cross-sectional setting, knee synovitis was assessed using 3-Tesla MRI and correlated with pain using the knee injury and osteoarthritis outcome score (KOOS). Synovitis was assessed in the peripatellar recesses with: (i) dynamic contrast-enhanced (DCE)-MRI, using both pharmacokinetic and heuristic models, (ii) contrast-enhanced (CE)-MRI, and (iii) non-CE-MRI. The DCE-MRI variable IRExNvoxel was chosen as the primary variable in the analyses.
  
  
  RESULTS
  Valid data were available in 94 persons with a mean age of 65 years, a BMI of 32.3kg/m(2) and a mean Kellgren-Lawrence grade of 2.5. IRExNvoxel showed a statically significant correlation with KOOS-Pain (r=-0.34; p=0.001), as was the case with all DCE-variables but one. Correlations between static MRI-variables and KOOS-Pain ranged between -0.21<r<-0.29 (p<0.040). Intraclass correlation coefficients ranged between 0.90-0.99 for the heuristic and 0.66-0.93 for the pharmacokinetic DCE-MRI variables.
  
  
  CONCLUSIONS
  The results confirm an association between peripatellar-synovitis and pain in KOA. Overall, DCE-MRI showed stronger correlations with KOOS-Pain compared to static MRI. DCE-MRI analyses were highly reproducible and have the potential to be used to further investigate the role of inflammation and perfusion in KOA.
authors.affiliation: The Parker Institute, Copenhagen University Hospital, Bispebjerg-Frederiksberg, Nordre Fasanvej 57, DK-2000 Frederiksberg, Denmark; Department of Radiology, Copenhagen University Hospital, Bispebjerg-Frederiksberg, Nordre Fasanvej 57, DK-2000 Frederiksberg, Denmark.
authors.forename: Robert G C
authors.initials: RG
authors.lastname: Riis
authors.affiliation: The Parker Institute, Copenhagen University Hospital, Bispebjerg-Frederiksberg, Nordre Fasanvej 57, DK-2000 Frederiksberg, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Gudbergsen
authors.affiliation: The Parker Institute, Copenhagen University Hospital, Bispebjerg-Frederiksberg, Nordre Fasanvej 57, DK-2000 Frederiksberg, Denmark.
authors.forename: Marius
authors.initials: M
authors.lastname: Henriksen
authors.affiliation: The Parker Institute, Copenhagen University Hospital, Bispebjerg-Frederiksberg, Nordre Fasanvej 57, DK-2000 Frederiksberg, Denmark.
authors.forename: Christine
authors.initials: C
authors.lastname: Ballegaard
authors.affiliation: The Parker Institute, Copenhagen University Hospital, Bispebjerg-Frederiksberg, Nordre Fasanvej 57, DK-2000 Frederiksberg, Denmark.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Bandak
authors.affiliation: Image Analysis Ltd., QABC Minster House, 272-274 Vauxhall Bridge Road, London SW1 V 1BA, United Kingdom.
authors.forename: Diana
authors.initials: D
authors.lastname: Röttger
authors.affiliation: The Parker Institute, Copenhagen University Hospital, Bispebjerg-Frederiksberg, Nordre Fasanvej 57, DK-2000 Frederiksberg, Denmark.
authors.forename: Henning
authors.initials: H
authors.lastname: Bliddal
authors.affiliation: The Parker Institute, Copenhagen University Hospital, Bispebjerg-Frederiksberg, Nordre Fasanvej 57, DK-2000 Frederiksberg, Denmark.
authors.forename: Bjarke Brandt
authors.initials: BB
authors.lastname: Hansen
authors.affiliation: The Parker Institute, Copenhagen University Hospital, Bispebjerg-Frederiksberg, Nordre Fasanvej 57, DK-2000 Frederiksberg, Denmark; Department of Radiology, Copenhagen University Hospital, Bispebjerg-Frederiksberg, Nordre Fasanvej 57, DK-2000 Frederiksberg, Denmark.
authors.forename: Stine
authors.initials: S
authors.lastname: Hangaard
authors.affiliation: The Parker Institute, Copenhagen University Hospital, Bispebjerg-Frederiksberg, Nordre Fasanvej 57, DK-2000 Frederiksberg, Denmark; Department of Radiology, Copenhagen University Hospital, Bispebjerg-Frederiksberg, Nordre Fasanvej 57, DK-2000 Frederiksberg, Denmark. Electronic address: mikael.boesen@gmail.com.
authors.forename: Mikael
authors.initials: M
authors.lastname: Boesen
mesh_terms: D000368:Aged; D003287:Contrast Media / Q000008:administration & dosage; D003430:Cross-Sectional Studies; D005260:Female; D005682:Gadolinium / Q000008:administration & dosage; D006571:Heterocyclic Compounds / Q000008:administration & dosage; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007719:Knee Joint / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds / Q000008:administration & dosage; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging*; D010147:Pain Measurement / Q000706:statistics & numerical data*; D010329:Patella / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D057566:Self Report; D013585:Synovitis / Q000000981:diagnostic imaging*
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C062402:gadoteridol; D005682:Gadolinium
keywords: Dynamic contrast-enhanced magnetic resonance imaging; Knee osteoarthritis; Magnetic resonance imaging; Pain; Synovitis