title: Optimal Filum Terminale Thickness Cutoff Value on Sonography for Lipoma Screening in Young Children.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the normal thickness of the filum terminale on sonography and suggest an optimal cutoff value for filum terminale lipoma screening in young children.
  
  
  METHODS
  We retrospectively reviewed lumbosacral sonograms and magnetic resonance images from children younger than 36 months that were obtained between January 2013 and June 2014. The filum terminale thickness on sonography and the presence of fat in the filum terminale on magnetic resonance imaging were evaluated.
  
  
  RESULTS
  From 111 children (mean age ± SD, 3.6 ± 3.0 months), 49 did not have abnormal lesions (normal group), and 62 had fat infiltration in the filum terminale (lipoma group). The filum terminale was thicker in the lipoma group than the normal group (1.5 ± 0.5 versus 0.9 ± 0.2 mm; P < .001). Filum terminale thickness also showed significance in a multivariable analysis with sex and age (odds ratio per 0.1-mm unit, 2.754; P < .001) and in propensity score matching for age (P < .001). The optimal cutoff value for filum terminale lipoma screening was 1.1 mm, with 94% sensitivity and 86% specificity.
  
  
  CONCLUSIONS
  The conventional cutoff value of 2 mm for a thickened filum terminale on sonography can be too thick. We suggest an optimal cutoff value of 1.1 mm for lipoma screening in young children.
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital (H.J.S., M.-J.K., H.G.K., M.-J.L.), and Biostatistics Collaboration Unit (H.S.L.), Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyun Joo
authors.initials: HJ
authors.lastname: Shin
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital (H.J.S., M.-J.K., H.G.K., M.-J.L.), and Biostatistics Collaboration Unit (H.S.L.), Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Myung-Joon
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital (H.J.S., M.-J.K., H.G.K., M.-J.L.), and Biostatistics Collaboration Unit (H.S.L.), Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital (H.J.S., M.-J.K., H.G.K., M.-J.L.), and Biostatistics Collaboration Unit (H.S.L.), Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyun Gi
authors.initials: HG
authors.lastname: Kim
authors.affiliation: Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital (H.J.S., M.-J.K., H.G.K., M.-J.L.), and Biostatistics Collaboration Unit (H.S.L.), Yonsei University College of Medicine, Seoul, Korea. mjl1213@yuhs.ac.
authors.forename: Mi-Jung
authors.initials: MJ
authors.lastname: Lee
mesh_terms: D002420:Cauda Equina / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007223:Infant; D008067:Lipoma / Q000000981:diagnostic imaging*; D008068:Lipomatosis / Q000150:complications / Q000000981:diagnostic imaging*; D008161:Lumbosacral Region / Q000000981:diagnostic imaging; D008297:Male; D008403:Mass Screening / Q000379:methods; D009436:Neural Tube Defects / Q000150:complications / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography
keywords: children; filum terminale; lipoma; magnetic resonance imaging; pediatric ultrasound; sonography