title: Relative volume measured with magnetic resonance imaging is an articular collapse predictor in hematological pediatric patients with femoral head osteonecrosis.
abstract: OBJECTIVE
  To assess the potential value of femoral head (FH) volume measurements to predict joint collapse, as compared to articular surface involvement, in post-treatment osteonecrosis (ON) in pediatric patients affected by lymphoproliferative diseases.
  
  
  METHODS
  Considering 114 young patients with lymphoproliferative diseases undergone a lower-limbs magnetic resonance imaging (MRI) examination between November 2006 and August 2012 for a suspected post-treatment ON, we finally considered a total of 13 cases (7 males, mean age 15.2 ± 4.8 years), which developed a FH ON lesions (n = 23). The MRI protocol included coronal short tau inversion recovery and T1-weighted sequences, from the hips to the ankles. During the follow-up (elapsed time: 9.2 ± 2 mo), 13/23 FH articular surface (FHS) developed articular deformity. The first MRI studies with diagnosis of ON were retrospectively analyzed, measuring FH volume (FHV), FHS, ON volume (ONV) and the articular surface involved by ON (ONS). The relative involvement of FHS, in terms of volume [relative volume (RV): ONV/FHV] and articular surface [relative surface (RS): ONS/FHS], was then calculated.
  
  
  RESULTS
  By using receiver operating characteristic curve analysis (threshold of 23% of volume involvement), RV predicted articular deformity in 13/13 FHS [sensitivity 100%, specificity 90%, accuracy 95%, positive predictive value (PPV) 93%, negative predictive value (NPV) 100%]. Considering a threshold of 50% of articular involvement, RS predicted articular deformity in 10/13 femoral heads (sensitivity 77%, specificity 100%, accuracy 87%, PPV 100%, NPV 77%).
  
  
  CONCLUSIONS
  RV might be a more reliable parameter than RS in predicting FH deformity and could represent a potential complementary diagnostic tool in the follow-up of femoral heads ON lesions.
authors.affiliation: Davide Ippolito, Alessandro Masetto, Cammillo Talei Franzesi, Pietro A Bonaffini, Alessandra Casiraghi, Sandro Sironi, Department of Diagnostic Radiology, School of Medicine, San Gerardo Hospital, University of Milano-Bicocca, 20900 Monza, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Ippolito
authors.affiliation: Davide Ippolito, Alessandro Masetto, Cammillo Talei Franzesi, Pietro A Bonaffini, Alessandra Casiraghi, Sandro Sironi, Department of Diagnostic Radiology, School of Medicine, San Gerardo Hospital, University of Milano-Bicocca, 20900 Monza, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Masetto
authors.affiliation: Davide Ippolito, Alessandro Masetto, Cammillo Talei Franzesi, Pietro A Bonaffini, Alessandra Casiraghi, Sandro Sironi, Department of Diagnostic Radiology, School of Medicine, San Gerardo Hospital, University of Milano-Bicocca, 20900 Monza, Italy.
authors.forename: Cammillo
authors.initials: C
authors.lastname: Talei Franzesi
authors.affiliation: Davide Ippolito, Alessandro Masetto, Cammillo Talei Franzesi, Pietro A Bonaffini, Alessandra Casiraghi, Sandro Sironi, Department of Diagnostic Radiology, School of Medicine, San Gerardo Hospital, University of Milano-Bicocca, 20900 Monza, Italy.
authors.forename: Pietro A
authors.initials: PA
authors.lastname: Bonaffini
authors.affiliation: Davide Ippolito, Alessandro Masetto, Cammillo Talei Franzesi, Pietro A Bonaffini, Alessandra Casiraghi, Sandro Sironi, Department of Diagnostic Radiology, School of Medicine, San Gerardo Hospital, University of Milano-Bicocca, 20900 Monza, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Casiraghi
authors.affiliation: Davide Ippolito, Alessandro Masetto, Cammillo Talei Franzesi, Pietro A Bonaffini, Alessandra Casiraghi, Sandro Sironi, Department of Diagnostic Radiology, School of Medicine, San Gerardo Hospital, University of Milano-Bicocca, 20900 Monza, Italy.
authors.forename: Sandro
authors.initials: S
authors.lastname: Sironi
keywords: Articular surface; Femoral head; Lymphoproliferative diseases; Magnetic resonance imaging; Osteonecrosis; Volume