title: Perfusion MRI in Early Stage of Legg-Calvé-Perthes Disease to Predict Lateral Pillar Involvement: A Preliminary Study.
abstract: BACKGROUND
  Current radiographic classifications for Legg-Calvé-Perthes disease cannot be applied at the early stages of the disease. The purpose of this study was to quantify the perfusion of the femoral epiphysis in the early stages of Legg-Calvé-Perthes disease with use of perfusion magnetic resonance imaging (MRI) and to determine if the extent of epiphyseal perfusion can predict the lateral pillar involvement at the mid-fragmentation stage.
  
  
  METHODS
  Twenty-nine patients had gadolinium-enhanced perfusion MRI at the initial stage or early fragmentation stage of Legg-Calvé-Perthes disease and were followed prospectively. The percent perfusion of the whole epiphysis and its lateral third was measured by four independent observers using image analysis software. The radiographs obtained at the mid-fragmentation stage were used for the lateral pillar classification. Intraclass correlation coefficient (ICC) and logistic regression analyses were performed.
  
  
  RESULTS
  The mean age (and standard deviation) at diagnosis was 7.7 ± 1.7 years (range, 5.3 to 11.3 years). The mean interval between the MRI and the time of maximum fragmentation was 8.2 ± 5.5 months. The interobserver ICC for the percent perfusion of the lateral third of the epiphysis was 0.90 (95% confidence interval [CI]: 0.83 to 0.95). The mean percent perfusion of the lateral third of the epiphysis was 92% ± 2%, 68% ± 18%, and 46% ± 12% for the hips in which the lateral pillar was later classified as A, B, and C, respectively (p = 0.001). When the perfusion level was ≥90% in the lateral third of the epiphysis, the odds ratio of the lateral pillar being later classified as group A, as opposed to B or C, was 72.0 (CI: 3.5 to 1476). With a perfusion level of ≤55% in the lateral third of the epiphysis, the odds ratio of the lateral pillar being later classified as group C, as opposed to A or B, was 33.3 (CI: 2.8 to 392). Similar results were obtained for the whole epiphysis.
  
  
  CONCLUSIONS
  Perfusion MRI measurements of the total epiphysis and its lateral third obtained at the early stages of Legg-Calvé-Perthes disease were predictive of lateral pillar involvement at the mid-fragmentation stage of the disease.
  
  
  METHODS
  Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Center of Excellence in Hip Disorders (H.K.W.K., K.D.W., V.K., J.B., E.C., C.B., H.I., J.D., A.L., and J.A.H.) and Department of Radiology (M.D.), Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219. E-mail address for H.K.W. Kim: harry.kim@tsrh.org.
authors.forename: Harry K W
authors.initials: HK
authors.lastname: Kim
authors.affiliation: Center of Excellence in Hip Disorders (H.K.W.K., K.D.W., V.K., J.B., E.C., C.B., H.I., J.D., A.L., and J.A.H.) and Department of Radiology (M.D.), Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219. E-mail address for H.K.W. Kim: harry.kim@tsrh.org.
authors.forename: Kathryn D
authors.initials: KD
authors.lastname: Wiesman
authors.affiliation: Center of Excellence in Hip Disorders (H.K.W.K., K.D.W., V.K., J.B., E.C., C.B., H.I., J.D., A.L., and J.A.H.) and Department of Radiology (M.D.), Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219. E-mail address for H.K.W. Kim: harry.kim@tsrh.org.
authors.forename: Vedant
authors.initials: V
authors.lastname: Kulkarni
authors.affiliation: Center of Excellence in Hip Disorders (H.K.W.K., K.D.W., V.K., J.B., E.C., C.B., H.I., J.D., A.L., and J.A.H.) and Department of Radiology (M.D.), Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219. E-mail address for H.K.W. Kim: harry.kim@tsrh.org.
authors.forename: Jamie
authors.initials: J
authors.lastname: Burgess
authors.affiliation: Center of Excellence in Hip Disorders (H.K.W.K., K.D.W., V.K., J.B., E.C., C.B., H.I., J.D., A.L., and J.A.H.) and Department of Radiology (M.D.), Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219. E-mail address for H.K.W. Kim: harry.kim@tsrh.org.
authors.forename: Elena
authors.initials: E
authors.lastname: Chen
authors.affiliation: Center of Excellence in Hip Disorders (H.K.W.K., K.D.W., V.K., J.B., E.C., C.B., H.I., J.D., A.L., and J.A.H.) and Department of Radiology (M.D.), Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219. E-mail address for H.K.W. Kim: harry.kim@tsrh.org.
authors.forename: Case
authors.initials: C
authors.lastname: Brabham
authors.affiliation: Center of Excellence in Hip Disorders (H.K.W.K., K.D.W., V.K., J.B., E.C., C.B., H.I., J.D., A.L., and J.A.H.) and Department of Radiology (M.D.), Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219. E-mail address for H.K.W. Kim: harry.kim@tsrh.org.
authors.forename: Haseeb
authors.initials: H
authors.lastname: Ikram
authors.affiliation: Center of Excellence in Hip Disorders (H.K.W.K., K.D.W., V.K., J.B., E.C., C.B., H.I., J.D., A.L., and J.A.H.) and Department of Radiology (M.D.), Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219. E-mail address for H.K.W. Kim: harry.kim@tsrh.org.
authors.forename: Jerry
authors.initials: J
authors.lastname: Du
authors.affiliation: Center of Excellence in Hip Disorders (H.K.W.K., K.D.W., V.K., J.B., E.C., C.B., H.I., J.D., A.L., and J.A.H.) and Department of Radiology (M.D.), Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219. E-mail address for H.K.W. Kim: harry.kim@tsrh.org.
authors.forename: Amanda
authors.initials: A
authors.lastname: Lu
authors.affiliation: 1149 Valley Quail Circle, San Jose, CA 95120.
authors.forename: Ashok V
authors.initials: AV
authors.lastname: Kulkarni
authors.affiliation: Center of Excellence in Hip Disorders (H.K.W.K., K.D.W., V.K., J.B., E.C., C.B., H.I., J.D., A.L., and J.A.H.) and Department of Radiology (M.D.), Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219. E-mail address for H.K.W. Kim: harry.kim@tsrh.org.
authors.forename: Molly
authors.initials: M
authors.lastname: Dempsey
authors.affiliation: Center of Excellence in Hip Disorders (H.K.W.K., K.D.W., V.K., J.B., E.C., C.B., H.I., J.D., A.L., and J.A.H.) and Department of Radiology (M.D.), Texas Scottish Rite Hospital for Children, 2222 Welborn Street, Dallas, TX 75219. E-mail address for H.K.W. Kim: harry.kim@tsrh.org.
authors.forename: J Anthony
authors.initials: JA
authors.lastname: Herring
mesh_terms: D002648:Child; D002675:Child, Preschool; D004838:Epiphyses / Q000000981:diagnostic imaging; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D007873:Legg-Calve-Perthes Disease / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D018810:Magnetic Resonance Angiography; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies