title: MR signal intensity characteristics in Legg-Calvé-Perthes disease. Value of fat-suppressed (STIR) images and contrast-enhanced T1-weighted images.
abstract: OBJECTIVE
  To evaluate the MR signal intensity characteristics in Legg-Calvé-Perthes disease on fat-suppressed (STIR) images and contrast-enhanced T1-weighted spin-echo images, and to develop criteria for the administration of contrast material.
  
  
  METHODS
  Twenty children with Legg-Calvé-Perthes disease underwent conventional radiography and MR imaging of the hip utilizing fat-suppressed (STIR) sequences and T1-weighted spin-echo sequences before and after i.v. contrast administration. The signal intensity characteristics of the femoral head and the proximal femoral metaphysis were assessed retrospectively by two pediatric radiologists.
  
  
  RESULTS
  Evaluation of the MR images revealed six different signal patterns within the femoral head: 1) isointense signal on all images; 2) complete signal void on all images; 3) hyperintense signal on STIR images with; or 4) without contrast enhancement on T1-weighted spin-echo images; 5) isointense signal on STIR images with; or 6) without contrast enhancement on T1-weighted images. Within the metaphysis three different signal patterns were differentiated.
  
  
  CONCLUSIONS
  Combination of fat-suppressed (STIR) sequences and T1-weighted pre- and post-contrast sequences allows an accurate evaluation of Legg-Calvé-Perthes disease. In patients without signal alterations or complete signal loss on fat-suppressed and T1-weighted spin-echo images, administration of i.v. contrast is not necessary. In case of bone marrow edema on fat-supressed images, contrast-enhanced T1-weighted images are required to identify viable osseous fragments.
authors.affiliation: Department of Diagnostic Radiology, University Hospital, University of Technology, Aachen, Germany.
authors.forename: A H
authors.initials: AH
authors.lastname: Mahnken
authors.forename: G
authors.initials: G
authors.lastname: Staatz
authors.forename: N
authors.initials: N
authors.lastname: Ihme
authors.forename: R W
authors.initials: RW
authors.lastname: Günther
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007873:Legg-Calve-Perthes Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011859:Radiography; D012189:Retrospective Studies