title: Detection of cartilage damage in femoroacetabular impingement with standardized dGEMRIC at 3 T.
abstract: OBJECTIVE
  This study aimed at identifying the optimal threshold value to detect cartilage lesions with Standardized delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) at 3 T and evaluate intra- and inter-observer repeatability.
  
  
  METHODS
  We retrospectively reviewed 20 hips in 20 patients. dGEMRIC maps were acquired at 3 T along radial imaging planes of the hip and standardized to remove the effects of patient's age, sex and diffusion of gadolinium contrast. Two observers separately evaluated 84 Standardized dGEMRIC maps, both by visual inspection and using an average index for a region of interest (ROI) in the acetabular cartilage. A radiologist evaluated the acetabular cartilage on morphologic MR images at exactly the same locations. Using intra-operative findings as reference, the optimal threshold to detect cartilage lesions with Standardized dGEMRIC was assessed and results were compared with the diagnostic performance of morphologic magnetic resonance imaging (MRI).
  
  
  RESULTS
  Using z < -2 as threshold and visual inspection of the color-adjusted maps, sensitivity, specificity and accuracy for Observer 1 and Observer 2, were 83%, 60% and 75%, and 69%, 70% and 69%, respectively. Overall performance was 52%, 67% and 58%, when using an average z for the acetabular cartilage, compared to 37%, 90% and 56% for morphologic assessment. The kappa coefficient was 0.76 and 0.68 for intra- and inter-observer repeatability, respectively, indicating substantial agreement.
  
  
  CONCLUSIONS
  Standardized dGEMRIC at 3 T is accurate in detecting cartilage damage and could improve preoperative assessment in femoroacetabular impingement (FAI). As cartilage lesions in FAI are localized, visual inspection of the Standardized dGEMRIC maps is more accurate than an average z for the acetabular cartilage.
authors.affiliation: The Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY 10016, USA; Department of Radiology, New York University Langone Medical Center, 550 First Avenue, New York, NY 10016, USA. Electronic address: Riccardo.Lattanzi@nyumc.org.
authors.forename: R
authors.initials: R
authors.lastname: Lattanzi
authors.affiliation: Department of Radiology, New York University Langone Medical Center, 550 First Avenue, New York, NY 10016, USA.
authors.forename: C
authors.initials: C
authors.lastname: Petchprapa
authors.affiliation: The Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY 10016, USA.
authors.forename: D
authors.initials: D
authors.lastname: Ascani
authors.affiliation: Department of Radiology, New York University Langone Medical Center, 550 First Avenue, New York, NY 10016, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Babb
authors.affiliation: Department of Radiology, New York University Langone Medical Center, 550 First Avenue, New York, NY 10016, USA.
authors.forename: D
authors.initials: D
authors.lastname: Chu
authors.affiliation: Department of Orthopedic Surgery, New York University Hospital for Joint Diseases, 301 East 17th Street, New York, NY 10003, USA.
authors.forename: R I
authors.initials: RI
authors.lastname: Davidovitch
authors.affiliation: Department of Orthopedic Surgery, New York University Hospital for Joint Diseases, 301 East 17th Street, New York, NY 10003, USA.
authors.forename: T
authors.initials: T
authors.lastname: Youm
authors.affiliation: Department of Orthopedic Surgery, New York University Hospital for Joint Diseases, 301 East 17th Street, New York, NY 10003, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Meislin
authors.affiliation: Department of Radiology, New York University Langone Medical Center, 550 First Avenue, New York, NY 10016, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Recht
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D057925:Femoracetabular Impingement / Q000175:diagnosis*; D019786:Gadolinium DTPA; D006621:Hip Joint / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
keywords: Femoroacetabular impingement; Hip articular cartilage; Hip imaging; MRI; Standardized dGEMRIC; dGEMRIC