title: MR measurement of articular cartilage thickness distribution in the hip.
abstract: OBJECTIVE
  To develop a method to determine the distribution of articular cartilage in the hip and to evaluate the potential of the method in a study of normal weight-bearing effects in asymptomatic young volunteers.
  
  
  METHODS
  Six volunteers were scanned after periods of standing and lying supine, using 3D gradient-echo magnetic resonance imaging (MRI). The protocol was repeated for two successive weeks to determine reproducibility. The femoral and acetabular cartilage layers were segmented as a single unit and thickness distribution maps were calculated using a spherical bone model as a frame of reference. Thickness maps were combined over the population using the bone model and post-weight-bearing and post-resting maps were compared.
  
  
  RESULTS
  Mean thickness values were compared using an analysis of variance and a significant increase in cartilage thickness of 0.05 mm (P=0.02) was observed. The reproducibility of the method, assessed using test-retest coefficient of variation was 2.5%.
  
  
  CONCLUSIONS
  The technique is reproducible, sensitive to sub-millimetre changes in thickness and may be useful in monitoring changes due to disease progression in patients with arthritis of the hip.
authors.affiliation: Imaging Science and Biomedical Engineering, University of Manchester, Stopford Building, Oxford Road, Manchester, M13 9PT, UK. josephine.naish@manchester.ac.uk
authors.forename: J H
authors.initials: JH
authors.lastname: Naish
authors.forename: E
authors.initials: E
authors.lastname: Xanthopoulos
authors.forename: C E
authors.initials: CE
authors.lastname: Hutchinson
authors.forename: J C
authors.initials: JC
authors.lastname: Waterton
authors.forename: C J
authors.initials: CJ
authors.lastname: Taylor
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D005260:Female; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016474:Weight-Bearing