title: Fovea alta on MR images: is it a marker of hip dysplasia in young adults?
abstract: OBJECTIVE
  The objective of our study was to investigate the association between high fovea capitis (fovea alta) and hip dysplasia in young adults.
  
  
  METHODS
  In a retrospective study, blinded observers reviewed 82 pelvic radiographic and hip MRI studies of three groups of patients: those with developmental dysplasia of the hip (DDH) (center-edge angle, ≤20°), those with borderline DDH (center-edge angle, 21°-25°), and control patients (center-edge angle, >25°). The center-edge angle and coxa valga (femoral neck-shaft angle, >135°) were assessed on pelvic radiographs, and fovea alta was assessed on MR images (delta angle, ≤10°). The Mann-Whitney and Fisher exact tests were used to correlate fovea alta with DDH and with coxa valga, respectively. Interobserver agreement for center-edge and delta angles and the diagnostic performance of fovea alta as a marker of DDH were calculated.
  
  
  RESULTS
  Thirty-one patients with DDH, 23 with borderline DDH, and 28 without DDH were included. Excellent interobserver agreement was found for center-edge angle (concordance correlation coefficient, 0.94) and for delta angle (concordance correlation coefficient, 0.91). Fovea alta had a significant association with DDH (p<0.001) but no association with coxa valga (p>0.57). A significant difference (p<0.001) was found between patients with DDH (3.4°) and those without DDH (21.7°) with respect to mean delta angle measurements. Fovea alta had 69.4% sensitivity, 82.1% specificity, 67.2% positive predictive value, 81.0% negative predictive value, and 75.6% overall accuracy as an indicator of DDH.
  
  
  CONCLUSIONS
  Fovea alta shows promise as a strong MRI marker of DDH.
authors.affiliation: Department of Radiology, New York University Hospital for Joint Diseases, New York University Langone Medical Center, 660 First Ave, Rm 218, New York, NY 10016, USA. Luis.Beltran@nyumc.org
authors.forename: Luis S
authors.initials: LS
authors.lastname: Beltran
authors.forename: Jason D
authors.initials: JD
authors.lastname: Mayo
authors.forename: Zehava S
authors.initials: ZS
authors.lastname: Rosenberg
authors.forename: Maria Diaz
authors.initials: MD
authors.lastname: De Tuesta
authors.forename: Olga
authors.initials: O
authors.lastname: Martin
authors.forename: Luis P
authors.initials: LP
authors.lastname: Neto
authors.forename: Jenny T
authors.initials: JT
authors.lastname: Bencardino
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000473:pathology; D000293:Adolescent; D000328:Adult; D060906:Coxa Valga / Q000175:diagnosis / Q000209:etiology; D061827:Dimensional Measurement Accuracy; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging / Q000473:pathology*; D006618:Hip Dislocation, Congenital / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D015588:Observer Variation; D015207:Osteoarthritis, Hip / Q000209:etiology; D010384:Pelvic Bones / Q000000981:diagnostic imaging; D011859:Radiography; D055815:Young Adult