title: A pilot, two-year longitudinal study of the interrelationship between trabecular bone and articular cartilage in the osteoarthritic knee.
abstract: OBJECTIVE
  To examine the relationship between structural changes of trabecular bone and cartilage, in patients with varying degrees of osteoarthritis (OA) over 2 years, using magnetic resonance imaging.
  
  
  METHODS
  High-resolution, axial images were acquired for assessing trabecular bone structure, using a 3-D fast gradient-echo sequence. High-resolution, fat-suppressed, sagittal images were acquired for assessing cartilage structure, using a 3-D spoiled gradient-echo sequence. In a subset of the patients, sagittal images were acquired for measuring T(2) relaxation time, using a 2-D dual-echo spin echo sequence.
  
  
  RESULTS
  A large variation in bone and cartilage parameters is evident among individual subjects in each group, however, group-specific means demonstrate decreasing trends (in bone and cartilage parameters) in osteoarthritic subjects (especially in mild OA subjects). The mean T(2) increased significantly (P<0.05) between the baseline and follow-up exams for all cartilage compartments except the lateral tibia. A positive relationship was established between cartilage changes and localized bone changes closest to the joint line, while a negative relationship was established between cartilage changes and global bone changes farthest from the joint line.
  
  
  CONCLUSIONS
  This study quantifies the changes in bone and cartilage structural parameters over time, and demonstrates a longitudinal relationship between the morphological changes in bone and cartilage structure in patients with varying degrees of OA. Although a large variation of bone and cartilage changes is apparent among subjects, significant trends are evident in a relatively small sample size, with a short follow-up duration.
authors.affiliation: Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology, University of California, San Francisco, CA 94107, USA. gabby@mrsc.ucsf.edu
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Blumenkrantz
authors.forename: Colleen T
authors.initials: CT
authors.lastname: Lindsey
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Dunn
authors.forename: Hua
authors.initials: H
authors.lastname: Jin
authors.forename: Michael D
authors.initials: MD
authors.lastname: Ries
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Link
authors.forename: Lynne S
authors.initials: LS
authors.lastname: Steinbach
authors.forename: Sharmila
authors.initials: S
authors.lastname: Majumdar
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001842:Bone and Bones / Q000473:pathology*; D002358:Cartilage, Articular / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology*