title: A new method to analyze dGEMRIC measurements in femoroacetabular impingement: preliminary validation against arthroscopic findings.
abstract: OBJECTIVE
  To validate a new method to analyze delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) measurements in the hip for early assessment of cartilage defects in femoroacetabular impingement (FAI).
  
  
  METHODS
  We performed a retrospective review of 10 hips in 10 FAI patients, who underwent hip arthroscopy. T1-weighted images and dGEMRIC T(1) maps were acquired at 1.5 T on coronal planes, including the anterior-superior, superior, posterior-superior hip cartilage. For all slices, a region of interest (ROI) was defined over the central portion of the femoral cartilage, assumed to be healthy, and T1 values (x) were transformed to standard scores (z) using z = (x -μ)/σ, where μ and σ are the average and standard deviation of T1 in the femoral ROI. Diagnostic performance of the resulting standardized dGEMRIC maps was evaluated against intraoperative findings and compared with that of a previously proposed dGEMRIC analysis as well as morphologic assessment.
  
  
  RESULTS
  Assuming z = -2 or z = -3 as the threshold between normal and degenerated cartilage, sensitivity, specificity and accuracy were 88%, 51% and 62%, and 71%, 63% and 65%, respectively. By using T1 = 500 ms as single threshold for all dGEMRIC T1 maps, these values became 47%, 58% and 55%, whereas they were 47%, 79% and 70% for morphologic evaluation.
  
  
  CONCLUSIONS
  Standardized dGEMRIC can increase the sensitivity in detecting abnormal cartilage in FAI and has the potential to improve the clinical interpretation of dGEMRIC measurements in FAI, by removing the effect of inter- and intra-patient T1 variability.
authors: The Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY 10016, USA. Riccardo.Lattanzi@nyumc.org
authors: R
authors: R
authors: Lattanzi
authors: C
authors: C
authors: Petchprapa
authors: C
authors: C
authors: Glaser
authors: K
authors: K
authors: Dunham
authors: A V
authors: AV
authors: Mikheev
authors: A
authors: A
authors: Krigel
authors: T C
authors: TC
authors: Mamisch
authors: Y-J
authors: YJ
authors: Kim
authors: H
authors: H
authors: Rusinek
authors: M
authors: M
authors: Recht
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy / Q000379:methods*; D002358:Cartilage, Articular / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D057925:Femoracetabular Impingement / Q000175:diagnosis*; D005682:Gadolinium; D006621:Hip Joint / Q000473:pathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D003287:Contrast Media; D005682:Gadolinium