title: In vivo rat knee cartilage volume measurement using quantitative high resolution MRI (7 T): feasibility and reproducibility.
abstract: OBJECTIVE
  to assess reliability and reproducibility of quantitative MRI (7 T) in assessing rat femoro-tibial cartilage volume.
  
  
  METHODS
  5 healthy rat knees were scanned in vivo using a 7 T experimental imager. Sagittal high resolution 3D Gradient Echo with fat suppression sequences were performed with a dedicated home-made 2-elements array coil. 3D MRI sets were used to perform manual segmentation of the 3 cartilage compartments (femoral groove, medial and lateral tibial plateaus) by using a tactile screen. To evaluate inter- and intra-observer reproducibilities, the segmentation procedure was done blindly by two trained observers. One observer repeated the operation twice, with a period of 10 months between both readings.
  
  
  RESULTS
  the mean duration to manually segment all the slices covering the cartilaginous joint was 4 hours. On the one hand, the inter-observer root mean square of coefficients of variation was 9.1%, 6.2%, 9.6% for the femoral, medial and lateral tibial compartments respectively. On the other hand, the intra-observer reproducibility was 2.1%, 3.2%, 2.5% for these cartilage compartments cited above.
  
  
  CONCLUSIONS
  the image quality obtained at 7 Teslas with our dedicated coil allowed segmentation of the cartilage compartments with good reproducibility. This study demonstrated that MRI is a useful technology to provide a non-invasive and reliable assessment of rat knee cartilage volume.
authors.affiliation: UMR 7561 CNRS - Nancy Université, Vandoeuvre lès Nancy, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Goebel
authors.forename: Radu
authors.initials: R
authors.lastname: Bolbos
authors.forename: Astrid
authors.initials: A
authors.lastname: Pinzano
authors.forename: Mathilde
authors.initials: M
authors.lastname: Schaeffer
authors.forename: Adrian
authors.initials: A
authors.lastname: Rengle
authors.forename: Laurent
authors.initials: L
authors.lastname: Galois
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Etienne
authors.forename: Patrick
authors.initials: P
authors.lastname: Netter
authors.forename: Damien
authors.initials: D
authors.lastname: Loeuille
authors.forename: Olivier
authors.initials: O
authors.lastname: Beuf
authors.forename: Pierre
authors.initials: P
authors.lastname: Gillet
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D007089:Image Enhancement / Q000295:instrumentation*; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods; D007719:Knee Joint / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D008297:Male; D009929:Organ Size; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity