title: High-Definition Fiber Tractography in Evaluation and Surgical Planning of Thalamopeduncular Pilocytic Astrocytomas in Pediatric Population: Case Series and Review of Literature.
abstract: OBJECTIVE
  Thalamopeduncular tumors (TPTs) of childhood present a challenge for neurosurgeons due to their eloquent location. Preoperative fiber tracking provides total or near-total resection, without additional neurologic deficit. High-definition fiber tractography (HDFT) is an advanced white matter imaging technique derived from magnetic resonance imaging diffusion data, shown to overcome the limitations of diffusion tensor imaging. We aimed to investigate alterations of corticospinal tract (CST) and medial lemniscus (ML) caused by TPTs and to demonstrate the application of HDFT in preoperative planning.
  
  
  METHODS
  Three pediatric patients with TPTs were enrolled. CSTs and MLs were evaluated for displacement, infiltration, and disruption. The relationship of these tracts to tumors was identified and guided surgical planning. Literature was reviewed for publications on pediatric thalamic and TPTs that used diffusion imaging.
  
  
  RESULTS
  Two patients had histologic diagnosis of pilocytic astrocytoma. One patient whose imaging suggested a low-grade glioma was managed conservatively. All tracts were displaced (1 CST anteriorly, 2 CSTs, 1 ML anteromedially, 1 ML medially, and 1 ML posteromedially). Literature review revealed 2 publications with 15 pilocytic astrocytoma cases, which investigated CST only. The condition of sensory pathway or anteromedial displacement of the CST in these tumors was not reported previously.
  
  
  CONCLUSIONS
  Displacement patterns of the perilesional fiber bundles by TPTs are not predictable. Fiber tracking, preferably HDFT, should be part of preoperative planning to achieve maximal extent of resection for longer survival rates in this young group of patients, while preserving white matter tracts and thus quality of life.
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA; Division of Pediatric Neurosurgery, Department of Neurosurgery, Gazi University Faculty of Medicine, Besevler, Ankara, Turkey. Electronic address: drceltikci@gmail.com.
authors.forename: Emrah
authors.initials: E
authors.lastname: Celtikci
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Pinar
authors.initials: P
authors.lastname: Celtikci
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: David Tiago
authors.initials: DT
authors.lastname: Fernandes-Cabral
authors.affiliation: Division of Pediatric Neurosurgery, Department of Radiology, Gazi University Faculty of Medicine, Besevler, Ankara, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Ucar
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Fernandez-Miranda
authors.affiliation: Division of Pediatric Neurosurgery, Department of Neurosurgery, Gazi University Faculty of Medicine, Besevler, Ankara, Turkey.
authors.forename: Alp Ozgun
authors.initials: AO
authors.lastname: Borcek
mesh_terms: D000293:Adolescent; D001254:Astrocytoma / Q000473:pathology* / Q000601:surgery; D001932:Brain Neoplasms / Q000473:pathology*; D065850:Cerebral Peduncle / Q000473:pathology / Q000601:surgery; D002675:Child, Preschool; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D006801:Humans; D056784:Leukoencephalopathies / Q000473:pathology / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods; D010347:Patient Care Planning; D025321:Surgery, Computer-Assisted / Q000379:methods; D013786:Thalamic Diseases / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome
keywords: Diffusion tensor imaging; High-definition fiber tractography; Pediatric; Pilocytic astrocytoma; Thalamopeduncular