title: Association of changes in delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) with changes in cartilage thickness in the medial tibiofemoral compartment of the knee: a 2 year follow-up study using 3.0 T MRI.
abstract: OBJECTIVE
  To determine the association between changes in the delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) index over 2 years as a measure of cartilage proteoglycan concentration, with changes in cartilage thickness in the medial tibiofemoral compartment of knees in middle-aged women.
  
  
  METHODS
  One hundred and forty-eight women (one knee for each subject) aged ≥40 years were included. 3.0 T MR images of the knee were acquired at baseline, 1 year and 2 years. Three-dimensional (3D) spoiled gradient recalled echo (SPGR) sequences (for cartilage thickness) and 3D inversion recovery-prepared SPGR sequences after dGEMRIC were acquired. Segmentation was performed in the medial central (weight-bearing) femur and tibia to determine cartilage proteoglycan concentration and thickness. The association of change in the dGEMRIC indices between baseline and 1-year follow-up with (a) concomitant changes in cartilage thickness and (b) change in cartilage thickness between 1 and 2 years was assessed using linear regression.
  
  
  RESULTS
  In the whole-sample model, a decrease in dGEMRIC indices over time at the central medial femur significantly predicted an increase in cartilage thickness at both the central medial femur (p=0.008) and the medial tibia (p=0.04).
  
  
  CONCLUSIONS
  A decrease in dGEMRIC indices was associated with an increase in cartilage thickness in the medial compartment. Our results suggest that an increase in cartilage thickness may also be related to a decrease in proteoglycan concentration, which may represent swelling of cartilage in early stages of degeneration.
authors.affiliation: Department of Radiology, Quantitative Imaging Center, Boston University School of Medicine, Boston, Massachusetts, USA Boston Imaging Core Lab, Boston, Massachusetts, USA Department of Radiology, Hospital do Coração (HCor) and Teleimagem, São Paulo, Brazil.
authors.forename: Michel D
authors.initials: MD
authors.lastname: Crema
authors.affiliation: Department of Rheumatology, Northern Clinical School, University of Sydney, Sydney, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Hunter
authors.affiliation: Clinical Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Deborah
authors.initials: D
authors.lastname: Burstein
authors.affiliation: Department of Radiology, Quantitative Imaging Center, Boston University School of Medicine, Boston, Massachusetts, USA Department of Radiology, University of Erlangen, Erlangen, Germany.
authors.forename: Frank W
authors.initials: FW
authors.lastname: Roemer
authors.affiliation: Division of Research, New England Baptist Hospital, Boston, Massachusetts, USA.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.affiliation: Institute of Anatomy and Musculoskeletal Research, Paracelsus Medical University, Salzburg, Austria Chondrometrics GmbH, Ainring, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Eckstein
authors.affiliation: Clinical Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Nitya
authors.initials: N
authors.lastname: Krishnan
authors.affiliation: Pfizer Global Research and Development, New London, Connecticut, USA.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Hellio Le-Graverand
authors.affiliation: Department of Radiology, Quantitative Imaging Center, Boston University School of Medicine, Boston, Massachusetts, USA Boston Imaging Core Lab, Boston, Massachusetts, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Guermazi
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology*; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology*; D016022:Case-Control Studies; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D019786:Gadolinium DTPA; D006801:Humans; D007719:Knee Joint / Q000378:metabolism / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000378:metabolism / Q000473:pathology*; D011509:Proteoglycans / Q000378:metabolism
chemical_list: D003287:Contrast Media; D011509:Proteoglycans; D019786:Gadolinium DTPA
keywords: Knee Osteoarthritis; Magnetic Resonance Imaging; Osteoarthritis