title: Zonal T2* and T1Gd assessment of knee joint cartilage in various histological grades of cartilage degeneration: an observational in vitro study.
abstract: OBJECTIVE
  Accurate assessment of cartilage status is increasingly becoming important to clinicians for offering joint preservation surgeries versus joint replacements. The goal of this study was to evaluate the validity of three-dimensional (3D), gradient-echo (GRE)-based T2* and T1Gd mapping for the assessment of various histological severities of degeneration in knee joint cartilage with potential implications for clinical management.
  
  
  METHODS
  MRI and histological assessment were conducted in 36 ex vivo lateral femoral condyle specimens. The MRI protocol included a 3D GRE multiecho data image combination sequence in order to assess the T2* decay, a 3D double-echo steady-state sequence for assessment of cartilage morphology, and a dual flip angle 3D GRE sequence with volumetric interpolated breathhold examination for the T1Gd assessment. The histological sample analysis was performed according to the Mankin system. The data were then analysed statistically and correlated.
  
  
  RESULTS
  We observed a significant decrease in the T2* and T1Gd values with increasing grades of cartilage degeneration (p<0.001) and a moderate correlation between T2* (r=0.514)/T1Gd (r=0.556) and the histological grading of cartilage degeneration (p<0.001). In addition, we noted a zonal variation in the T2* and T1Gd values reflecting characteristic zonal differences in the biochemical composition of hyaline cartilage.
  
  
  CONCLUSIONS
  This study outlines the potential of GRE-based T2* and T1Gd mapping to identify various grades of cartilage damage. Early changes in specific zones may assist clinicians in identifying methods of early intervention involving the targeted joint preservation approach versus moving forward with unicompartmental, bicompartmental or tricompartmental joint replacement procedures.
  
  
  BACKGROUND
  DRKS00000729.
authors: Medical Faculty, Department of Orthopaedics, University Düsseldorf, Düsseldorf, Germany.
authors: Bernd
authors: B
authors: Bittersohl
authors: Center of Hip Preservation and Children's Orthopaedics, San Diego, California, USA.
authors: Harish S
authors: HS
authors: Hosalkar
authors: Medical Faculty, Department of Diagnostic and Interventional Radiology, University Düsseldorf, Düsseldorf, Germany.
authors: Falk R
authors: FR
authors: Miese
authors: Medical Faculty, Department of Orthopaedics, University Düsseldorf, Düsseldorf, Germany.
authors: Jonas
authors: J
authors: Schibensky
authors: LVR Clinic for Orthopedic Surgery, Viersen, Germany.
authors: Dietmar P
authors: DP
authors: König
authors: Medical Faculty, Clinic for Vascular and Endovascular Surgery, University Münster, Münster, Germany.
authors: Monika
authors: M
authors: Herten
authors: Medical Faculty, Department of Diagnostic and Interventional Radiology, University Düsseldorf, Düsseldorf, Germany.
authors: Gerald
authors: G
authors: Antoch
authors: Medical Faculty, Department of Orthopaedics, University Düsseldorf, Düsseldorf, Germany.
authors: Rüdiger
authors: R
authors: Krauspe
authors: Medical Faculty, Department of Orthopaedics, University Düsseldorf, Düsseldorf, Germany.
authors: Christoph
authors: C
authors: Zilkens
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002357:Cartilage Diseases / Q000473:pathology*; D002358:Cartilage, Articular / Q000473:pathology*; D005269:Femur / Q000473:pathology*; D006801:Humans; D066298:In Vitro Techniques; D007717:Knee / Q000473:pathology*; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012720:Severity of Illness Index