Orientation entropy analysis of diffusion tensor in healthy and myelopathic spinal cord

Jiao Long Cui, Chunyi Wen, Yong Hu, Kin Cheung Mak, Ka Hung Henry Mak, Keith Dip Kei Luk

Research output: Journal article publicationJournal articleAcademic researchpeer-review

19 Citations (Scopus)

Abstract

The majority of nerve fibers in the spinal cord run longitudinally, playing an important role in connecting the brain to the peripheral nerves. There is a growing interest in applying diffusion tensor imaging (DTI) to the evaluation of spinal cord microarchitecture. The current study sought to compare the organization of longitudinal nerve fibers between healthy and myelopathic spinal cords using entropy-based analysis of principal eigenvector mapping. A total of 22 subjects were recruited, including 14 healthy subjects, seven cervical myelopathy (CM) patients with single-level compression, and one patient suffering from multi-level compression. Diffusion tensor magnetic resonance (MR) images of the cervical spinal cord were obtained using a pulsed gradient, spin-echo echo-planar imaging (SE-EPI) sequence with a 3T MR system. Regions of interest (ROIs) were drawn manually to cover the spinal cord, and Shannon entropy was calculated in principal eigenvector maps. The results revealed no significant differences in orientation entropy values along the whole length of cervical spinal cord in healthy subjects (C2-3: 0.73 ± 0.05; C3-4: 0.71 ± 0.07; C4-5: 0.72 ± 0.048; C5-6: 0.71 ± 0.07; C6-7: 0.72 ± 0.07). In contrast, orientation entropy values in myelopathic cord were significantly higher at the compression site (0.91 ± 0.03), and the adjacent levels (above: 0.85 ± 0.03; below: 0.83 ± 0.05). This study provides a novel approach to analyze the orientation information in diffusion MR images of healthy and diseased spinal cord. These results indicate that orientation entropy can be applied to determine the contribution of each compression level to the overall disorganization of principal nerve tracts of myelopathic spinal cord in cases with multi-level compression.
Original languageEnglish
Pages (from-to)1028-1033
Number of pages6
JournalNeuroImage
Volume58
Issue number4
DOIs
Publication statusPublished - 15 Oct 2011
Externally publishedYes

Keywords

  • Cervical myelopathy
  • Diffusion tensor imaging
  • Eigenvector
  • Orientation entropy
  • Spinal cord

ASJC Scopus subject areas

  • Cognitive Neuroscience
  • Neurology

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