title: Cartilage repair surgery: outcome evaluation by using noninvasive cartilage biomarkers based on quantitative MRI techniques?
abstract: BACKGROUND
  New quantitative magnetic resonance imaging (MRI) techniques are increasingly applied as outcome measures after cartilage repair.
  
  
  OBJECTIVE
  To review the current literature on the use of quantitative MRI biomarkers for evaluation of cartilage repair at the knee and ankle.
  
  
  METHODS
  Using PubMed literature research, studies on biochemical, quantitative MR imaging of cartilage repair were identified and reviewed.
  
  
  RESULTS
  Quantitative MR biomarkers detect early degeneration of articular cartilage, mainly represented by an increasing water content, collagen disruption, and proteoglycan loss. Recently, feasibility of biochemical MR imaging of cartilage repair tissue and surrounding cartilage was demonstrated. Ultrastructural properties of the tissue after different repair procedures resulted in differences in imaging characteristics. T2 mapping, T1rho mapping, delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), and diffusion weighted imaging (DWI) are applicable on most clinical 1.5 T and 3 T MR scanners. Currently, a standard of reference is difficult to define and knowledge is limited concerning correlation of clinical and MR findings. The lack of histological correlations complicates the identification of the exact tissue composition.
  
  
  CONCLUSIONS
  A multimodal approach combining several quantitative MRI techniques in addition to morphological and clinical evaluation might be promising. Further investigations are required to demonstrate the potential for outcome evaluation after cartilage repair.
authors.affiliation: Department of Radiology, Klinikum Rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany.
authors.forename: Pia M
authors.initials: PM
authors.lastname: Jungmann
authors.affiliation: Department of Radiology, Klinikum Rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Baum
authors.affiliation: Department of Neuroradiology, Klinikum Rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany.
authors.forename: Jan S
authors.initials: JS
authors.lastname: Bauer
authors.affiliation: Department of Radiology, Klinikum Rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany.
authors.forename: Dimitrios C
authors.initials: DC
authors.lastname: Karampinos
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University Medical Center, Albert-Ludwigs Universitaet Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany.
authors.forename: Benjamin
authors.identifier: 0000-0001-8524-6779
authors.initials: B
authors.lastname: Erdle
authors.affiliation: Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Link
authors.affiliation: Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, USA.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Li
authors.affiliation: MR Center, Department of Radiology, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna, Austria.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Trattnig
authors.affiliation: Department of Radiology, Klinikum Rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany.
authors.forename: Ernst J
authors.initials: EJ
authors.lastname: Rummeny
authors.affiliation: Department of Radiology, Klinikum Rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Woertler
authors.affiliation: MR Center, Department of Radiology, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna, Austria ; Department of Trauma Surgery, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Krankenhausstrasse 12, 91054 Erlangen, Germany.
authors.forename: Goetz H
authors.initials: GH
authors.lastname: Welsch
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D002356:Cartilage / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000601:surgery*; D003094:Collagen / Q000378:metabolism; D003287:Contrast Media / Q000627:therapeutic use; D005682:Gadolinium / Q000627:therapeutic use; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D039781:PubMed; D011859:Radiography; D014867:Water / Q000378:metabolism
chemical_list: D015415:Biomarkers; D003287:Contrast Media; D014867:Water; D003094:Collagen; D005682:Gadolinium