title: T2 mapping in the knee after microfracture at 3.0 T: correlation of global T2 values and clinical outcome - preliminary results.
abstract: OBJECTIVE
  The aim of our study was to correlate global T2 values of microfracture repair tissue (RT) with clinical outcome in the knee joint.
  
  
  METHODS
  We assessed 24 patients treated with microfracture in the knee joint. Magnetic resonance (MR) examinations were performed on a 3T MR unit, T2 relaxation times were obtained with a multi-echo spin-echo technique. T2 maps were obtained using a pixel wise, mono-exponential non-negative least squares fit analysis. Slices covering the cartilage RT were selected and region of interest analysis was done. An individual T2 index was calculated with global mean T2 of the RT and global mean T2 of normal, hyaline cartilage. The Lysholm score and the International Knee Documentation Committee (IKDC) knee evaluation forms were used for the assessment of clinical outcome. Bivariate correlation analysis and a paired, two tailed t test were used for statistics.
  
  
  RESULTS
  Global T2 values of the RT [mean 49.8ms, standards deviation (SD) 7.5] differed significantly (P<0.001) from global T2 values of normal, hyaline cartilage (mean 58.5ms, SD 7.0). The T2 index ranged from 61.3 to 101.5. We found the T2 index to correlate with outcome of the Lysholm score (r(s)=0.641, P<0.001) and the IKDC subjective knee evaluation form (r(s)=0.549, P=0.005), whereas there was no correlation with the IKDC knee form (r(s)=-0.284, P=0.179).
  
  
  CONCLUSIONS
  These findings indicate that T2 mapping is sensitive to assess RT function and provides additional information to morphologic MRI in the monitoring of microfracture.
authors.affiliation: Department of Orthopedics, Medical University of Vienna, Austria.
authors.forename: S E
authors.initials: SE
authors.lastname: Domayer
authors.forename: F
authors.initials: F
authors.lastname: Kutscha-Lissberg
authors.forename: G
authors.initials: G
authors.lastname: Welsch
authors.forename: R
authors.initials: R
authors.lastname: Dorotka
authors.forename: S
authors.initials: S
authors.lastname: Nehrer
authors.forename: C
authors.initials: C
authors.lastname: Gäbler
authors.forename: T C
authors.initials: TC
authors.lastname: Mamisch
authors.forename: S
authors.initials: S
authors.lastname: Trattnig
mesh_terms: D000328:Adult; D054544:Arthroplasty, Subchondral; D002356:Cartilage / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020127:Recovery of Function; D013223:Statistics as Topic; D014945:Wound Healing / Q000502:physiology*