title: Quantitative MRI criteria for optic pathway enlargement in neurofibromatosis type 1.
abstract: To determine quantitative size thresholds for enlargement of the optic nerve, chiasm, and tract in children with neurofibromatosis type 1 (NF1).
  
  
  
  Children 0.5-18.6 years of age who underwent high-resolution T1-weighted MRI were eligible for inclusion. This consisted of children with NF1 with or without optic pathway gliomas (OPGs) and a control group who did not have other acquired, systemic, or genetic conditions that could alter their anterior visual pathway (AVP). Maximum and average diameter and volume of AVP structures were calculated from reconstructed MRI images. Values above the 95th percentile from the controls were considered the threshold for defining an abnormally large AVP measure.
  
  
  
  A total of 186 children (controls = 82; NF1noOPG = 54; NF1+OPG = 50) met inclusion criteria. NF1noOPG and NF1+OPG participants demonstrated greater maximum optic nerve diameter and volume, optic chiasm volume, and total brain volume compared to controls (p < 0.05, all comparisons). Total brain volume, rather than age, predicted optic nerve and chiasm volume in controls (p < 0.05). Applying the 95th percentile threshold to all NF1 participants, the maximum optic nerve diameter (3.9 mm) and AVP volumes resulted in few false-positive errors (specificity >80%, all comparisons).
  
  
  
  Quantitative reference values for AVP enlargement will enhance the development of objective diagnostic criteria for OPGs secondary to NF1.
authors.affiliation: From the Center for Neuroscience and Behavior (R.A.A., R.J.P.), The Gilbert Family Neurofibromatosis Institute (R.A.A., R.J.P.), the Sheikh Zayed Institute for Pediatric Surgical Innovation (A.M., E.B., M.A.A., M.G.L.), and The Brain Tumor Institute (R.J.P.), Children's National Health System; The George Washington University (R.I.); and The George Washington University School of Medicine and Health Sciences (M.G.L.), Washington, DC. averyr@email.chop.edu.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Avery
authors.affiliation: From the Center for Neuroscience and Behavior (R.A.A., R.J.P.), The Gilbert Family Neurofibromatosis Institute (R.A.A., R.J.P.), the Sheikh Zayed Institute for Pediatric Surgical Innovation (A.M., E.B., M.A.A., M.G.L.), and The Brain Tumor Institute (R.J.P.), Children's National Health System; The George Washington University (R.I.); and The George Washington University School of Medicine and Health Sciences (M.G.L.), Washington, DC.
authors.forename: Awais
authors.initials: A
authors.lastname: Mansoor
authors.affiliation: From the Center for Neuroscience and Behavior (R.A.A., R.J.P.), The Gilbert Family Neurofibromatosis Institute (R.A.A., R.J.P.), the Sheikh Zayed Institute for Pediatric Surgical Innovation (A.M., E.B., M.A.A., M.G.L.), and The Brain Tumor Institute (R.J.P.), Children's National Health System; The George Washington University (R.I.); and The George Washington University School of Medicine and Health Sciences (M.G.L.), Washington, DC.
authors.forename: Rabia
authors.initials: R
authors.lastname: Idrees
authors.affiliation: From the Center for Neuroscience and Behavior (R.A.A., R.J.P.), The Gilbert Family Neurofibromatosis Institute (R.A.A., R.J.P.), the Sheikh Zayed Institute for Pediatric Surgical Innovation (A.M., E.B., M.A.A., M.G.L.), and The Brain Tumor Institute (R.J.P.), Children's National Health System; The George Washington University (R.I.); and The George Washington University School of Medicine and Health Sciences (M.G.L.), Washington, DC.
authors.forename: Elijah
authors.initials: E
authors.lastname: Biggs
authors.affiliation: From the Center for Neuroscience and Behavior (R.A.A., R.J.P.), The Gilbert Family Neurofibromatosis Institute (R.A.A., R.J.P.), the Sheikh Zayed Institute for Pediatric Surgical Innovation (A.M., E.B., M.A.A., M.G.L.), and The Brain Tumor Institute (R.J.P.), Children's National Health System; The George Washington University (R.I.); and The George Washington University School of Medicine and Health Sciences (M.G.L.), Washington, DC.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Alsharid
authors.affiliation: From the Center for Neuroscience and Behavior (R.A.A., R.J.P.), The Gilbert Family Neurofibromatosis Institute (R.A.A., R.J.P.), the Sheikh Zayed Institute for Pediatric Surgical Innovation (A.M., E.B., M.A.A., M.G.L.), and The Brain Tumor Institute (R.J.P.), Children's National Health System; The George Washington University (R.I.); and The George Washington University School of Medicine and Health Sciences (M.G.L.), Washington, DC.
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Packer
authors.affiliation: From the Center for Neuroscience and Behavior (R.A.A., R.J.P.), The Gilbert Family Neurofibromatosis Institute (R.A.A., R.J.P.), the Sheikh Zayed Institute for Pediatric Surgical Innovation (A.M., E.B., M.A.A., M.G.L.), and The Brain Tumor Institute (R.J.P.), Children's National Health System; The George Washington University (R.I.); and The George Washington University School of Medicine and Health Sciences (M.G.L.), Washington, DC.
authors.forename: Marius George
authors.initials: MG
authors.lastname: Linguraru
mesh_terms: D000293:Adolescent; D001921:Brain / Q000000981:diagnostic imaging / Q000254:growth & development; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009456:Neurofibromatosis 1 / Q000150:complications / Q000000981:diagnostic imaging*; D009900:Optic Nerve / Q000000981:diagnostic imaging* / Q000254:growth & development; D020339:Optic Nerve Glioma / Q000000981:diagnostic imaging / Q000209:etiology; D009929:Organ Size; D012189:Retrospective Studies; D055815:Young Adult