title: Change in knee cartilage T2 in response to mechanical loading.
abstract: OBJECTIVE
  To assess the clinical feasibility of magnetic resonance (MR) imaging with a mechanical loading system for evaluation of load-bearing function in knee joints using cartilage T2 as a surrogate of cartilage matrix changes.
  
  
  METHODS
  Sagittal T2 maps of the medial and lateral femorotibial joints of 22 healthy volunteers were obtained using 3.0T MR imaging. After preloading for 6-9 minutes, MR images under static loading conditions were obtained by applying axial compression force of 50% of body weight during imaging. T2 values of the femoral and tibial cartilage at the weight-bearing area were compared between unloading and loading conditions.
  
  
  RESULTS
  Under loading conditions, mean cartilage T2 decreased, depending on location of the knee cartilage. For the femoral side a significant decrease in T2 with loading was observed only at the region in direct contact with the opposing tibial cartilage, in the medial femoral cartilage (5.4%, P < 0.0005). For the tibial side a significant decrease in T2 with loading was widely observed in the medial and lateral joint, at regions both covered and not covered by the meniscus (4.3%-7.6%, P < 0.005).
  
  
  CONCLUSIONS
  MR imaging with mechanical loading is feasible to detect site-specific changes in cartilage T2 during static loading.
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka, Japan. nishii@ort.med.osaka-u.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishii
authors.forename: Kagayaki
authors.initials: K
authors.lastname: Kuroda
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Matsuoka
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Sahara
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000033:anatomy & histology* / Q000502:physiology; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology* / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D016474:Weight-Bearing / Q000502:physiology*