title: T2* mapping of acetabular and femoral hip joint cartilage at 3 T: a prospective controlled study.
abstract: OBJECTIVE
  The aim of this study was to identify the pattern of T2* values in acetabular and femoral head cartilage in morphologically normal and abnormal zones at 3 T.
  
  
  METHODS
  Twenty-nine patients (mean [SD] age, 30.8 [8.8] years) with symptomatic femoroacetabular impingement and suspected cartilage damage (study group) and 35 healthy, asymptomatic volunteers (mean [SD] age, 24.9 [2.1] years) with no obvious history of hip diseases or abnormalities (control group) were included. Magnetic resonance imaging was performed at 3 T using a 3-dimensional (3D) double-echo steady-state sequence for grading cartilage morphologically and a 3D multiecho data image combination sequence for T2* assessment. Statistical assessment included the Student t test to reveal differences between mean T2* values of the study group and the control group. One-way analysis of variance was used to identify any statistically significant differences between the T2* values in various grades (modified Outerbridge score system) of cartilage damage within the study group.
  
  
  RESULTS
  Significant differences were noted between the T2* values in the study group and the control group (P < 0.001). We also noted a significant drop in T2* in accordance with the morphologic damage in the study group (P < 0.001). The largest drop in T2* was found between morphologically normal-appearing cartilage (grade 0; T2*, 25.2 milliseconds) and grade I changes (T2*, 18.1 milliseconds) (P < 0.001).
  
  
  CONCLUSIONS
  In combination with a 3-T system, T2* mapping offers unique advantages such as high image resolution and the ability of 3D biochemically sensitive cartilage evaluation in the hip joint without the need for contrast medium. Given these advantages, we believe that T2* mapping is another welcome addition to the rapidly evolving era of hip cartilage biochemical imaging. Further studies are necessary that involve a diagnostic histological analysis as gold standard for comparison.
authors.affiliation: Department of Orthopedics, University Dusseldorf, Medical Faculty, Dusseldorf, Germany. bbittersohl@partners.org
authors.forename: Bernd
authors.initials: B
authors.lastname: Bittersohl
authors.forename: Falk R
authors.initials: FR
authors.lastname: Miese
authors.forename: Harish S
authors.initials: HS
authors.lastname: Hosalkar
authors.forename: Tallal C
authors.initials: TC
authors.lastname: Mamisch
authors.forename: Gerald
authors.initials: G
authors.lastname: Antoch
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Krauspe
authors.forename: Christoph
authors.initials: C
authors.lastname: Zilkens
mesh_terms: D000077:Acetabulum / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D002358:Cartilage, Articular / Q000473:pathology*; D016022:Case-Control Studies; D016001:Confidence Intervals; D017352:Echo-Planar Imaging / Q000379:methods; 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; D007592:Joint Diseases / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013223:Statistics as Topic; D055815:Young Adult