title: Magnetic resonance T(1 rho) imaging of osteoarthritis: a rabbit ACL transection model.
abstract: OBJECTIVE
  The objective of this study was to develop quantitative T(1 rho)-weighted magnetic resonance imaging methodology for the detection and characterization of cartilage degeneration in a rabbit anterior cruciate ligament (ACL) transection model.
  
  
  METHODS
  The right knee ACLs of 18 adult female New Zealand white rabbits were transected. The left knee joint served as a sham control. The rabbits were euthanized at 3 (Group 1), 6 (Group 2) and 12 (Group 3) weeks postoperatively. High-resolution 3D fat-saturated spoiled gradient echo images and T(1 rho)-weighted images were obtained in both the sagittal and axial planes at 3 T using a quadrature wrist coil. Following MR analysis, histological slides from the lateral femoral condyle cartilage were graded using the Mankin grading system.
  
  
  RESULTS
  For all three groups, the average overall T(1 rho) values were significantly higher in the ACL-transected knee compared to control knee, and the percentage differences in T(1 rho) values between ACL-transected and control increased with the duration of time after transection. The average Mankin score for ACL-transected knees was higher than that for control for each time point, but this difference was statistically significant only for all groups combined.
  
  
  CONCLUSIONS
  This study demonstrates the feasibility of using T(1 rho)-weighted imaging as a useful tool in the detection and quantification of cartilage damage in all knee compartments in an ACL-transected rabbit model of cartilage degeneration.
authors.affiliation: University of California, San Francisco School of Medicine, San Francisco, CA 94158, USA.
authors.forename: Jesus
authors.initials: J
authors.lastname: Lozano
authors.forename: Ehsan
authors.initials: E
authors.lastname: Saadat
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Li
authors.forename: Sharmila
authors.initials: S
authors.lastname: Majumdar
authors.forename: C Benjamin
authors.initials: CB
authors.lastname: Ma
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000473:pathology* / Q000601:surgery*; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D020370:Osteoarthritis, Knee / Q000175:diagnosis*; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity