title: Cartilage T1ρ and T2 Relaxation Times in Patients With Mild-to-Moderate Radiographic Hip Osteoarthritis.
abstract: OBJECTIVE
  To analyze region-specific T1ρ and T2 relaxation times of the hip joint cartilage in relation to presence or absence of radiographic hip osteoarthritis (OA) and presence or absence of magnetic resonance imaging (MRI)-detected cartilage defects.
  
  
  METHODS
  Weight-bearing radiographs and 3T MRI studies of the hip were obtained from 84 volunteers. Based on Kellgren/Lawrence (K/L) scoring of the radiographs, 54 subjects were classified as healthy controls (K/L grade ≤1) and 30 were classified as having mild or moderate radiographic hip OA (K/L grades 2 or 3, respectively). Two-dimensional fat-suppressed fast spin-echo MRI sequences were used for semiquantitative clinical scoring of cartilage defects, and a T1ρ/T2 sequence was used to quantitatively assess the cartilage matrix. The femoral and acetabular cartilage was then segmented into 8 regions and the mean T1ρ/T2 values were calculated. Differences in T1ρ and T2 relaxation times were compared between subjects with and those without radiographic hip OA, and those with and those without femoral or acetabular cartilage defects.
  
  
  RESULTS
  Higher T1ρ and T2 relaxation times in the anterior superior and central regions of the acetabular cartilage were seen in individuals with radiographic hip OA and those with acetabular cartilage defects compared to their respective controls (P < 0.05). In the femoral cartilage, the differences in T1ρ and T2 were not significant for any of the comparisons. Significant differences in the T1ρ and T2 values (each P < 0.05) were found in more subregions of the cartilage and across the whole cartilage when subjects were stratified based on the presence of MRI-detected cartilage defects than when they were stratified based on the presence of radiographic hip OA.
  
  
  CONCLUSIONS
  T1ρ and T2 relaxation parameters are sensitive to the presence of cartilage degeneration. Both parameters may therefore support MRI evidence of cartilage defects of the hip.
authors.affiliation: University of California, San Francisco.
authors.forename: Cory
authors.initials: C
authors.lastname: Wyatt
authors.affiliation: University of California, San Francisco.
authors.forename: Deepak
authors.initials: D
authors.lastname: Kumar
authors.affiliation: University of California, San Francisco.
authors.forename: Karupppasamy
authors.initials: K
authors.lastname: Subburaj
authors.affiliation: University of California, San Francisco.
authors.forename: Sonia
authors.initials: S
authors.lastname: Lee
authors.affiliation: University of California, San Francisco.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Nardo
authors.affiliation: University of California, San Francisco.
authors.forename: Divya
authors.initials: D
authors.lastname: Narayanan
authors.affiliation: University of California, San Francisco.
authors.forename: Drew
authors.initials: D
authors.lastname: Lansdown
authors.affiliation: University of California, San Francisco.
authors.forename: Thomas
authors.initials: T
authors.lastname: Vail
authors.affiliation: University of California, San Francisco.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Link
authors.affiliation: University of California, San Francisco.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Souza
authors.affiliation: University of California, San Francisco.
authors.forename: Sharmila
authors.initials: S
authors.lastname: Majumdar
mesh_terms: D000328:Adult; D000368:Aged; D002358:Cartilage, Articular / Q000473:pathology*; D016022:Case-Control Studies; D003094:Collagen; D005260:Female; D006621:Hip Joint / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000473:pathology*; D011509:Proteoglycans; D011859:Radiography; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D011509:Proteoglycans; D003094:Collagen