title: Diffusion tensor imaging of the pediatric optic nerve: intrinsic and extrinsic pathology compared to normal controls.
abstract: OBJECTIVE
  To establish normative magnetic resonance diffusion tensor imaging (MRDTI) data in the pediatric optic nerve and compare to pathologic conditions both intrinsic and extrinsic to the anterior optic nerve pathway.
  
  
  METHODS
  A retrospective analysis of MRDTI at 3.0T in children ages 0-18 with both normal imaging studies and with pathologic conditions either arising from the optic nerves or exerting mass effect on the anterior optic pathways was performed. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained within the posterior part of the intraorbital optic nerves. Statistical analysis compared normal controls to optic pathway lesions.
  
  
  RESULTS
  Lesions intrinsic to the optic nerve including septo-optic dysplasia and optic nerve glioma demonstrated statistically significant reductions in FA and increases in ADC values. There was no statistically significant difference in FA or mean diffusivity between the normal controls and patients with lesions extrinsic to the optic nerve but exerting mass effect on the visual pathway.
  
  
  CONCLUSIONS
  MRDTI is a feasible technique for evaluating the optic nerves in pediatric patients. It may play a role in presurgical planning by demonstrating integrity of the visual pathway in patients with resectable lesions, allowing for minimization of morbidity associated with vision loss.
authors.affiliation: Department of Radiology, Fletcher Allen Healthcare/University of Vermont, Burlington, Vermont, USA. Joshua.nickerson@vtmednet.org
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Nickerson
authors.forename: Michael B
authors.initials: MB
authors.lastname: Salmela
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Koski
authors.forename: Trevor
authors.initials: T
authors.lastname: Andrews
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Filippi
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D016880:Anisotropy; D002648:Child; D002675:Child, Preschool; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009900:Optic Nerve / Q000033:anatomy & histology / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000473:pathology*; D012016:Reference Values; D012189:Retrospective Studies