title: Evaluation of native hyaline cartilage and repair tissue after two cartilage repair surgery techniques with 23Na MR imaging at 7 T: initial experience.
abstract: OBJECTIVE
  To compare the sodium normalized mean signal intensity (NMSI) values between patients after bone marrow stimulation (BMS) and matrix-associated autologous chondrocyte transplantation (MACT) cartilage repair procedures.
  
  
  METHODS
  Nine BMS and nine MACT patients were included. Each BMS patient was matched with one MACT patient according to age [BMS 36.7 ± 10.7 (mean ± standard deviation) years; MACT 36.9 ± 10.0 years], postoperative interval (BMS 33.5 ± 25.3 months; MACT 33.2 ± 25.7 months), and defect location. All magnetic resonance imaging (MRI) measurements were performed on a 7 T system. Proton images served for morphological evaluation of repair tissue using the magnetic resonance observation of cartilage repair tissue (MOCART) scoring system. Sodium NMSI values in the repair area and morphologically normal cartilage were calculated. Clinical outcome was assessed right after MRI. Analysis of covariance, t-tests, and Pearson correlation coefficients were evaluated.
  
  
  RESULTS
  Sodium NMSI was significantly lower in BMS (P = 0.004) and MACT (P = 0.006) repair tissue, compared to reference cartilage. Sodium NMSI was not different between the reference cartilage in MACT and BMS patients (P = 0.664), however it was significantly higher in MACT than in BMS repair tissue (P = 0.028). Better clinical outcome was observed in BMS than in MACT patients. There was no difference between MOCART scores for MACT and BMS patients (P = 0.915). We did not observe any significant correlation between MOCART score and sodium repair tissue NMSI (r = -0.001; P = 0.996).
  
  
  CONCLUSIONS
  Our results suggest higher glycosaminoglycan (GAG) content, and therefore, repair tissue of better quality in MACT than in BMS patients. Sodium imaging might be beneficial in non-invasive evaluation of cartilage repair surgery efficacy.
authors.affiliation: MR Centre-Highfield MR, Department of Radiology, Medical University of Vienna/Vienna General Hospital, Vienna, Austria. stefan.zbyn@meduniwien.ac.at
authors.forename: S
authors.initials: S
authors.lastname: Zbýň
authors.forename: D
authors.initials: D
authors.lastname: Stelzeneder
authors.forename: G H
authors.initials: GH
authors.lastname: Welsch
authors.forename: L L
authors.initials: LL
authors.lastname: Negrin
authors.forename: V
authors.initials: V
authors.lastname: Juras
authors.forename: M E
authors.initials: ME
authors.lastname: Mayerhoefer
authors.forename: P
authors.initials: P
authors.lastname: Szomolanyi
authors.forename: W
authors.initials: W
authors.lastname: Bogner
authors.forename: S E
authors.initials: SE
authors.lastname: Domayer
authors.forename: M
authors.initials: M
authors.lastname: Weber
authors.forename: S
authors.initials: S
authors.lastname: Trattnig
mesh_terms: D000328:Adult; D000368:Aged; D002358:Cartilage, Articular / Q000473:pathology; D019902:Chondrocytes / Q000637:transplantation*; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000473:pathology* / Q000601:surgery; D006801:Humans; D051457:Hyaline Cartilage / Q000473:pathology*; D021621:Imaging, Three-Dimensional / Q000379:methods; D007719:Knee Joint / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D014945:Wound Healing; D055815:Young Adult