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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Neurosci. | doi: 10.3389/fnins.2019.01254

Optic radiation tractography in pediatric brain surgery applications: a reliability and agreement assessment of the tractography method

 Joseph Y. Yang1, 2, 3*,  Richard Beare4, 5, Michelle H. Wu6*,  Sarah M. Barton3, 4, 7,  Charles B. Malpas4, 8, 9,  Chun-Hung Yeh10, A. S. Harvey3, 11, 12, Vicki Anderson3, 8, 13, 14, Wirginia J. Maixner1, 11 and Marc Seal3, 4
  • 1Department of Neurosurgery, Royal Children’s Hospital, Australia
  • 2Neuroscience research and Developmental Imaging groups, Murdoch Childrens Research Institute (MCRI), Australia
  • 3Department of Pediatrics, Melbourne Medical School, University of Melbourne, Australia
  • 4Developmental Imaging group, Murdoch Childrens Research Institute (MCRI), Australia
  • 5Department of Medicine, Monash University, Australia
  • 6Department of Medical Imaging, Royal Children’s Hospital, Australia
  • 7Department of Neurology, Royal Children’s Hospital, Australia
  • 8Melbourne School of Psychological Sciences, The University of Melbourne, Australia
  • 9Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Australia
  • 10Florey Institute of Neuroscience and Mental Health, University of Melbourne, Australia
  • 11Neuroscience Research group, Murdoch Childrens Research Institute (MCRI), Australia
  • 12Department of Neurology, Royal Melbourne Hospital, Australia
  • 13Clinical Sciences Theme, Brain and Mind group, Murdoch Childrens Research Institute (MCRI), Australia
  • 14Department of Psychology, Royal Children's Hospital, Australia

Background: Optic radiation (OR) tractography may help predict and reduce post-neurosurgical visual field deficits. OR tractography methods currently lack pediatric and surgical focus.

Purpose: We propose a clinically feasible OR tractography strategy in a pediatric neurosurgery setting and examine its intra-rater and inter-rater reliability/agreements.

Methods: Preoperative and intraoperative MRI data were obtained from six epilepsy and two brain tumor patients on 3 Tesla MRI scanners. Four raters with different clinical experience followed the proposed strategy to perform probabilistic OR tractography with manually drawing anatomical landmarks to reconstruct the OR pathway, based on fiber orientation distributions estimated from high angular resolution diffusion imaging data. Intra- and inter-rater reliabilities/agreements of tractography results were assessed using intraclass correlation coefficient (ICC) and dice similarity coefficient (DSC) across various tractography and OR morphological metrics, including the lateral geniculate body positions, tract volumes, and Meyer’s loop position from temporal anatomical landmarks.

Results: Good to excellent intra- and inter-rater reproducibility was demonstrated for the majority of OR reconstructions (ICC = 0.70–0.99; DSC = 0.84–0.89). ICC was higher for non-lesional (0.82–0.99) than lesional OR (0.70–0.99). The non-lesional OR’s mean volume was 22.66 cm3; the mean Meyer’s loop position was 29.4 mm from the temporal pole, 5.89 mm behind of and 10.26 mm in front of the temporal ventricular horn. The greatest variations (±1.00–3.00 mm) were observed near pathology, at the tract edges or at cortical endpoints. The OR tractography were used to assist surgical planning and guide lesion resection in all cases, no patient had new visual field deficits postoperatively.

Conclusion: The proposed tractography strategy generates reliable and reproducible OR tractography images that can be reliably implemented in the routine, non-emergency pediatric neurosurgical setting.

Keywords: diffusion MRI, tractography, Neurosurgery, meyer’s loop, Optic Radiation, Visual field deficits

Received: 20 Aug 2019; Accepted: 05 Nov 2019.

Copyright: © 2019 Yang, Beare, Wu, Barton, Malpas, Yeh, Harvey, Anderson, Maixner and Seal. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
PhD. Joseph Y. Yang, Department of Neurosurgery, Royal Children’s Hospital, Parkville, 3052, Victoria, Australia, joseph.yang@mcri.edu.au
Dr. Michelle H. Wu, Department of Medical Imaging, Royal Children’s Hospital, Parkville, 3052, Victoria, Australia, Michelle.Wu@rch.org.au