title: Is T1ρ Mapping an Alternative to Delayed Gadolinium-enhanced MR Imaging of Cartilage in the Assessment of Sulphated Glycosaminoglycan Content in Human Osteoarthritic Knees? An in Vivo Validation Study.
abstract: OBJECTIVE
  To determine if T1ρ mapping can be used as an alternative to delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the quantification of cartilage biochemical composition in vivo in human knees with osteoarthritis.
  
  
  METHODS
  This study was approved by the institutional review board. Written informed consent was obtained from all participants. Twelve patients with knee osteoarthritis underwent dGEMRIC and T1ρ mapping at 3.0 T before undergoing total knee replacement. Outcomes of dGEMRIC and T1ρ mapping were calculated in six cartilage regions of interest. Femoral and tibial cartilages were harvested during total knee replacement. Cartilage sulphated glycosaminoglycan (sGAG) and collagen content were assessed with dimethylmethylene blue and hydroxyproline assays, respectively. A four-dimensional multivariate mixed-effects model was used to simultaneously assess the correlation between outcomes of dGEMRIC and T1ρ mapping and the sGAG and collagen content of the articular cartilage.
  
  
  RESULTS
  T1 relaxation times at dGEMRIC showed strong correlation with cartilage sGAG content (r = 0.73; 95% credibility interval [CI] = 0.60, 0.83) and weak correlation with cartilage collagen content (r = 0.40; 95% CI: 0.18, 0.58). T1ρ relaxation times did not correlate with cartilage sGAG content (r = 0.04; 95% CI: -0.21, 0.28) or collagen content (r = -0.05; 95% CI = -0.31, 0.20).
  
  
  CONCLUSIONS
  dGEMRIC can help accurately measure cartilage sGAG content in vivo in patients with knee osteoarthritis, whereas T1ρ mapping does not appear suitable for this purpose. Although the technique is not completely sGAG specific and requires a contrast agent, dGEMRIC is a validated and robust method for quantifying cartilage sGAG content in human osteoarthritis subjects in clinical research.
authors.affiliation: From the Departments of Radiology (J.v.T., G.K., E.E.B., S.K., G.P.K., E.H.G.O.), Orthopedic Surgery (J.v.T., M.R., P.K.B., G.J.V.M.v.O., J.A.N.V.), Medical Informatics (E.E.B., S.K.), Biostatistics (K.N.), and Otorhinolaryngology (G.J.V.M.v.O.), Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands (H.W.); and Department of Orthopedics and Rheumatology, University Medical Center Utrecht, Utrecht, the Netherlands (H.W.).
authors.forename: Jasper
authors.initials: J
authors.lastname: van Tiel
authors.affiliation: From the Departments of Radiology (J.v.T., G.K., E.E.B., S.K., G.P.K., E.H.G.O.), Orthopedic Surgery (J.v.T., M.R., P.K.B., G.J.V.M.v.O., J.A.N.V.), Medical Informatics (E.E.B., S.K.), Biostatistics (K.N.), and Otorhinolaryngology (G.J.V.M.v.O.), Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands (H.W.); and Department of Orthopedics and Rheumatology, University Medical Center Utrecht, Utrecht, the Netherlands (H.W.).
authors.forename: Gyula
authors.initials: G
authors.lastname: Kotek
authors.affiliation: From the Departments of Radiology (J.v.T., G.K., E.E.B., S.K., G.P.K., E.H.G.O.), Orthopedic Surgery (J.v.T., M.R., P.K.B., G.J.V.M.v.O., J.A.N.V.), Medical Informatics (E.E.B., S.K.), Biostatistics (K.N.), and Otorhinolaryngology (G.J.V.M.v.O.), Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands (H.W.); and Department of Orthopedics and Rheumatology, University Medical Center Utrecht, Utrecht, the Netherlands (H.W.).
authors.forename: Max
authors.initials: M
authors.lastname: Reijman
authors.affiliation: From the Departments of Radiology (J.v.T., G.K., E.E.B., S.K., G.P.K., E.H.G.O.), Orthopedic Surgery (J.v.T., M.R., P.K.B., G.J.V.M.v.O., J.A.N.V.), Medical Informatics (E.E.B., S.K.), Biostatistics (K.N.), and Otorhinolaryngology (G.J.V.M.v.O.), Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands (H.W.); and Department of Orthopedics and Rheumatology, University Medical Center Utrecht, Utrecht, the Netherlands (H.W.).
authors.forename: Pieter K
authors.initials: PK
authors.lastname: Bos
authors.affiliation: From the Departments of Radiology (J.v.T., G.K., E.E.B., S.K., G.P.K., E.H.G.O.), Orthopedic Surgery (J.v.T., M.R., P.K.B., G.J.V.M.v.O., J.A.N.V.), Medical Informatics (E.E.B., S.K.), Biostatistics (K.N.), and Otorhinolaryngology (G.J.V.M.v.O.), Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands (H.W.); and Department of Orthopedics and Rheumatology, University Medical Center Utrecht, Utrecht, the Netherlands (H.W.).
authors.forename: Esther E
authors.initials: EE
authors.lastname: Bron
authors.affiliation: From the Departments of Radiology (J.v.T., G.K., E.E.B., S.K., G.P.K., E.H.G.O.), Orthopedic Surgery (J.v.T., M.R., P.K.B., G.J.V.M.v.O., J.A.N.V.), Medical Informatics (E.E.B., S.K.), Biostatistics (K.N.), and Otorhinolaryngology (G.J.V.M.v.O.), Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands (H.W.); and Department of Orthopedics and Rheumatology, University Medical Center Utrecht, Utrecht, the Netherlands (H.W.).
authors.forename: Stefan
authors.initials: S
authors.lastname: Klein
authors.affiliation: From the Departments of Radiology (J.v.T., G.K., E.E.B., S.K., G.P.K., E.H.G.O.), Orthopedic Surgery (J.v.T., M.R., P.K.B., G.J.V.M.v.O., J.A.N.V.), Medical Informatics (E.E.B., S.K.), Biostatistics (K.N.), and Otorhinolaryngology (G.J.V.M.v.O.), Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands (H.W.); and Department of Orthopedics and Rheumatology, University Medical Center Utrecht, Utrecht, the Netherlands (H.W.).
authors.forename: Kazem
authors.initials: K
authors.lastname: Nasserinejad
authors.affiliation: From the Departments of Radiology (J.v.T., G.K., E.E.B., S.K., G.P.K., E.H.G.O.), Orthopedic Surgery (J.v.T., M.R., P.K.B., G.J.V.M.v.O., J.A.N.V.), Medical Informatics (E.E.B., S.K.), Biostatistics (K.N.), and Otorhinolaryngology (G.J.V.M.v.O.), Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands (H.W.); and Department of Orthopedics and Rheumatology, University Medical Center Utrecht, Utrecht, the Netherlands (H.W.).
authors.forename: Gerjo J V M
authors.initials: GJ
authors.lastname: van Osch
authors.affiliation: From the Departments of Radiology (J.v.T., G.K., E.E.B., S.K., G.P.K., E.H.G.O.), Orthopedic Surgery (J.v.T., M.R., P.K.B., G.J.V.M.v.O., J.A.N.V.), Medical Informatics (E.E.B., S.K.), Biostatistics (K.N.), and Otorhinolaryngology (G.J.V.M.v.O.), Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands (H.W.); and Department of Orthopedics and Rheumatology, University Medical Center Utrecht, Utrecht, the Netherlands (H.W.).
authors.forename: Jan A N
authors.initials: JA
authors.lastname: Verhaar
authors.affiliation: From the Departments of Radiology (J.v.T., G.K., E.E.B., S.K., G.P.K., E.H.G.O.), Orthopedic Surgery (J.v.T., M.R., P.K.B., G.J.V.M.v.O., J.A.N.V.), Medical Informatics (E.E.B., S.K.), Biostatistics (K.N.), and Otorhinolaryngology (G.J.V.M.v.O.), Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands (H.W.); and Department of Orthopedics and Rheumatology, University Medical Center Utrecht, Utrecht, the Netherlands (H.W.).
authors.forename: Gabriel P
authors.initials: GP
authors.lastname: Krestin
authors.affiliation: From the Departments of Radiology (J.v.T., G.K., E.E.B., S.K., G.P.K., E.H.G.O.), Orthopedic Surgery (J.v.T., M.R., P.K.B., G.J.V.M.v.O., J.A.N.V.), Medical Informatics (E.E.B., S.K.), Biostatistics (K.N.), and Otorhinolaryngology (G.J.V.M.v.O.), Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands (H.W.); and Department of Orthopedics and Rheumatology, University Medical Center Utrecht, Utrecht, the Netherlands (H.W.).
authors.forename: Harrie
authors.initials: H
authors.lastname: Weinans
authors.affiliation: From the Departments of Radiology (J.v.T., G.K., E.E.B., S.K., G.P.K., E.H.G.O.), Orthopedic Surgery (J.v.T., M.R., P.K.B., G.J.V.M.v.O., J.A.N.V.), Medical Informatics (E.E.B., S.K.), Biostatistics (K.N.), and Otorhinolaryngology (G.J.V.M.v.O.), Erasmus University Medical Center, PO Box 2040, 3000 CA Rotterdam, the Netherlands; Department of Biomechanical Engineering, Delft University of Technology, Delft, the Netherlands (H.W.); and Department of Orthopedics and Rheumatology, University Medical Center Utrecht, Utrecht, the Netherlands (H.W.).
authors.forename: Edwin H G
authors.initials: EH
authors.lastname: Oei
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D001499:Bayes Theorem; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology*; D003094:Collagen / Q000378:metabolism; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006025:Glycosaminoglycans / Q000378:metabolism*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D011446:Prospective Studies
chemical_list: D003287:Contrast Media; D006025:Glycosaminoglycans; C013786:A73025; D003094:Collagen; D019786:Gadolinium DTPA