title: T2* mapping of hip joint cartilage in various histological grades of degeneration.
abstract: OBJECTIVE
  To evaluate T2* values in various histological severities of osteoarthritis (OA).
  
  
  METHODS
  Magnetic resonance imaging (MRI) and T2* mapping including a three-dimensional (3D) double-echo steady-state (DESS) sequence for morphological cartilage assessment and a 3D multiecho data image combination (MEDIC) sequence for T2* mapping were conducted in 21 human femoral head specimens with varying severities of OA. Subsequently, histological assessment was undertaken in all specimens to correlate the observations of T2* mapping with histological analyses. According to the Mankin score, four grades of histological changes were determined: grade 0 (Mankin scores of 0-4), grade I (scores of 5-8), grade II (scores of 9-10), and grade III (scores of 11-14). For reliability assessment, cartilage T2* measurements were repeated after 4 weeks in 10 randomly selected femoral head specimens.
  
  
  RESULTS
  T2* values decreased significantly with increasing cartilage degeneration (total P-values <0.001) ranging from 36.3 ± 4.3 ms in grade 0 regions to 22.8 ± 4.3 ms in regions with grade III changes. Pearson correlation analysis proved a fair correlation between T2* values and Mankin score (correlation coefficient = -0.362) that was statistically significant (P-value <0.001). Intra-class correlation (ICC) analysis demonstrated high intra-observer reproducibility for the T2* measurement (ICC: 0.949, P < 0.001).
  
  
  CONCLUSIONS
  Given the advantages of the T2* mapping technique with no need for contrast medium, high image resolution and ability to perform 3D biochemically sensitive imaging, T2* mapping may be a strong addition to the currently evolving era of cartilage biochemical imaging.
authors.affiliation: University Düsseldorf, Medical Faculty, Orthopedic Department, 40225 Dusseldorf, Germany. bbittersohl@partners.org
authors.forename: B
authors.initials: B
authors.lastname: Bittersohl
authors.forename: F R
authors.initials: FR
authors.lastname: Miese
authors.forename: H S
authors.initials: HS
authors.lastname: Hosalkar
authors.forename: M
authors.initials: M
authors.lastname: Herten
authors.forename: G
authors.initials: G
authors.lastname: Antoch
authors.forename: R
authors.initials: R
authors.lastname: Krauspe
authors.forename: C
authors.initials: C
authors.lastname: Zilkens
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D002358:Cartilage, Articular / Q000473:pathology*; D005260:Female; D005270:Femur Head / Q000473:pathology; D006621:Hip Joint / Q000473:pathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000473:pathology* / Q000601:surgery; D015203:Reproducibility of Results; D012720:Severity of Illness Index