Longitudinal study on diffusion tensor imaging and diffusion tensor tractography following spinal cord contusion injury in rats

Zhao, Chen; Rao, Jia‐Sheng; Pei, Xiao-Jiao; Lei, Jianfeng; Wang, Zhan-Jing; Yang, Zhaoyang; Li, Xiaoguang

doi:10.1007/s00234-016-1660-7

Cited by 33 publications

(29 citation statements)

References 34 publications

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“…Many rodent studies have reported the gradual decrease in the FA values of SCI epicenter with time, at the rostral/caudal levels; however, a drastic decrease in FA occurred on day 3 after SCI. The FA at the epicenter and the rostral/caudal levels was stable by day 7 post‐SCI and increased slowly with time . In our results, the sites also showed an upward trend or a downward trend, but the overall trend of most sites showed declination.…”

Section: Discussionsupporting

confidence: 51%

Degeneration of white matter and gray matter revealed by diffusion tensor imaging and pathological mechanism after spinal cord injury in canine

et al. 2018

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Section: Discussionsupporting

confidence: 51%

Degeneration of white matter and gray matter revealed by diffusion tensor imaging and pathological mechanism after spinal cord injury in canine

et al. 2018

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“…MRI studies in rats ex vivo indicated that FA decreased in both white matter and gray matter after 11 weeks and 24 weeks following SCI, especially at the injury epicenter (Ellingson et al, ; Jirjis et al, ). C. Zhao et al (C. Zhao et al, ) reported longitudinal variation in FA values at the epicenter and the rostral/caudal levels of the injured spinal cord in rats, and found differentially altered patterns at injury sites. At the epicenter, an obvious decrease in FA occurred only on day one after SCI.…”

Section: Discussionmentioning

confidence: 99%

Dynamic diffusion tensor imaging of spinal cord contusion: A canine model

Liu

Yang

et al. 2018

J of Neuroscience Research

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This study aimed to explore the dynamic diffusion tensor imaging (DTI) of changes in spinal cord contusion using a canine model of injury involving rostral and caudal levels. In this study, a spinal cord contusion model was established in female dogs using a custom-made weight-drop lesion device. DTI was performed on dogs with injured spinal cords (n=7) using a Siemens 3.0T MRI scanner at pre-contusion and at 3 h, 24 h, 6 weeks and 12 weeks post-injury. The tissue sections were stained for immunohistochemical analysis. Canine models of spinal cord contusion were created successfully using the weight-drop lesion device. The fractional anisotropy (FA) value of lesion epicenter decreased, while the apparent diffusion coefficient (ADC), mean diffusivity (MD), and radial diffusivity (RD) values increased, and the extent of the curve was apparent gradually. The site and time affected the DTI parameters significantly in the whole spinal cord, ADC (site, P < 0.001 and time, P = 0.077, respectively); FA (site, P < 0.001 and time, P = 0.002, respectively). Immunohistological analysis of GFAP and NF revealed the pathologic changes of reactive astrocytes and axons, as well as the cavity and glial scars occurring during chronic SCI. DTI is a sensitive and noninvasive imaging tool useful to assess edema, hemorrhage, cavity formation, structural damage and reconstruction of axon, and myelin in dogs. The DTI parameters after contusion vary. However, the curves of ADC, MD, and RD were nearly similar and the FA curve was distinct. All the DTI parameters were affected by distance and time.

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“…In the anisometric conditions, voxels had the same size in two of the dimensions (0.155 mm) and a larger size (0.930 mm) in the other. Similar values have been used previously [40–48]. The three anisometric voxels resulted from setting the larger size in the LR, SI and PA rat brain directions, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…It has been shown that a bias dependent on fiber bundle orientation is introduced if non-isometric voxels are acquired [38]. However, diffusion studies commonly use anisometric resolution (for example [39–48]) as it solves the limitation of the acquisition time for in vivo MRI studies [31]. Losing certain spatial resolution is less problematic when studying the human brain, as it has abundant and large white matter tracts.…”

Section: Introductionmentioning

confidence: 99%

Effects of Orientation and Anisometry of Magnetic Resonance Imaging Acquisitions on Diffusion Tensor Imaging and Structural Connectomes

et al. 2017

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Diffusion-weighted imaging (DWI) quantifies water molecule diffusion within tissues and is becoming an increasingly used technique. However, it is very challenging as correct quantification depends on many different factors, ranging from acquisition parameters to a long pipeline of image processing. In this work, we investigated the influence of voxel geometry on diffusion analysis, comparing different acquisition orientations as well as isometric and anisometric voxels. Diffusion-weighted images of one rat brain were acquired with four different voxel geometries (one isometric and three anisometric in different directions) and three different encoding orientations (coronal, axial and sagittal). Diffusion tensor scalar measurements, tractography and the brain structural connectome were analyzed for each of the 12 acquisitions. The acquisition direction with respect to the main magnetic field orientation affected the diffusion results. When the acquisition slice-encoding direction was not aligned with the main magnetic field, there were more artifacts and a lower signal-to-noise ratio that led to less anisotropic tensors (lower fractional anisotropic values), producing poorer quality results. The use of anisometric voxels generated statistically significant differences in the values of diffusion metrics in specific regions. It also elicited differences in tract reconstruction and in different graph metric values describing the brain networks. Our results highlight the importance of taking into account the geometric aspects of acquisitions, especially when comparing diffusion data acquired using different geometries.

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Longitudinal study on diffusion tensor imaging and diffusion tensor tractography following spinal cord contusion injury in rats

Abstract: FA was sensitive to degeneration in white matter and DTT could directly reflect the distribution of the residual white matter. Moreover, days 1 to 3 post-SCI may be the optimal time window for SCI examination and therapy.

Cited by 33 publications

References 34 publications

Degeneration of white matter and gray matter revealed by diffusion tensor imaging and pathological mechanism after spinal cord injury in canine

Degeneration of white matter and gray matter revealed by diffusion tensor imaging and pathological mechanism after spinal cord injury in canine

Dynamic diffusion tensor imaging of spinal cord contusion: A canine model

Effects of Orientation and Anisometry of Magnetic Resonance Imaging Acquisitions on Diffusion Tensor Imaging and Structural Connectomes

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