A 3D high resolution ex vivo white matter atlas of the common squirrel monkey (saimiri sciureus) based on diffusion tensor imaging

Diagnosis and management of peripheral nerve injury is complicated by the inability to assess microstructural features of injured nerve fibers via clinical examination and electrophysiology. Diffusion tensor imaging (DTI) has been shown to accurately detect nerve injury and regeneration in crush models of peripheral nerve injury, but no prior studies have been conducted on nerve transection, a surgical emergency that can lead to permanent weakness or paralysis. Acute sciatic nerve injuries were performed microsurgically to produce multiple grades of nerve transection in rats that were harvested 1 hour after surgery. High-resolution diffusion tensor images from ex vivo sciatic nerves were obtained using diffusion-weighted spin-echo acquisitions at 4.7 T. Fractional anisotropy was significantly reduced at the injury sites of transected rats compared with sham rats. Additionally, minor eigenvalues and radial diffusivity were profoundly elevated at all injury sites and were negatively correlated to the degree of injury. Diffusion tensor tractography showed discontinuities at all injury sites and significantly reduced continuous tract counts. These findings demonstrate that high-resolution DTI is a promising tool for acute diagnosis and grading of traumatic peripheral nerve injuries.

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Use of High Resolution 3D Diffusion Tensor Imaging to Study Brain White Matter Development in Live Neonatal Rats

Frontiers in Psychiatry ◽

10.3389/fpsyt.2011.00054 ◽

2011 ◽

Vol 2 ◽

Cited By ~ 8

Author(s):

Yu Cai ◽

Matthew S. McMurray ◽

Ipek Oguz ◽

Hong Yuan ◽

Martin A. Styner ◽

...

Keyword(s):

Diffusion Tensor Imaging ◽

White Matter ◽

High Resolution ◽

Diffusion Tensor ◽

Neonatal Rats ◽

Brain White Matter ◽

White Matter Development

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Diffusion tensor imaging analysis of the brain in the canine model of Krabbe disease

The Neuroradiology Journal ◽

10.1177/1971400916665378 ◽

2016 ◽

Vol 29 (6) ◽

pp. 417-424 ◽

Cited By ~ 6

Author(s):

Allison Bradbury ◽

David Peterson ◽

Charles Vite ◽

Steven Chen ◽

N Matthew Ellinwood ◽

...

Keyword(s):

Diffusion Tensor Imaging ◽

White Matter ◽

Mr Imaging ◽

Gray Matter ◽

Diffusion Tensor ◽

Ex Vivo ◽

Small Animal ◽

Krabbe Disease ◽

Adc Values ◽

The Brain

Purpose The goal of this study was to compare the diffusion tensor imaging (DTI) metrics from an end-stage canine Krabbe brain evaluated by MR imaging ex vivo to those of a normal dog brain. We hypothesized that the white matter of the canine Krabbe brain would show decreased fractional anisotropy (FA) values and increased apparent diffusion coefficient (ADC) and radial diffusivity (RD) values. Methods An 11-week-old Krabbe dog was euthanized after disease progression. The brain was removed and was placed in a solution of 10% formalin. MR imaging was performed and compared to the brain images of a normal dog that was similarly fixed post-mortem. Both brains were scanned using similar protocols on a 7 T small-animal MRI system. For each brain, maps of ADC, FA, and RD were calculated for 11 white-matter regions and five control gray-matter regions. Results Large decreases in FA values, increases in ADC values, and increases in RD (consistent with demyelination) values, were seen in white matter of the Krabbe brain but not gray matter. ADC values in gray matter of the Krabbe brain were decreased by approximately 29% but increased by approximately 3.6% in white matter of the Krabbe brain. FA values in gray matter were decreased by approximately 3.3% but decreased by approximately 29% in white matter. RD values were decreased by approximately 27.2% in gray matter but increased by approximately 20% in white matter. Conclusion We found substantial abnormalities of FA, ADC, and RD values in an ex vivo canine Krabbe brain.

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Identification of Severities of Spinal Cord Injury during Acute Phase in Rats by Diffusion Tensor Imaging

10.21203/rs.3.rs-17760/v1 ◽

2020 ◽

Author(s):

Beike Chen ◽

Qiang Tan ◽

Weikang Zhao ◽

Qiming Yang ◽

Hongyan Zhang ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Diffusion Tensor Imaging ◽

White Matter ◽

Diffusion Tensor ◽

Motor Evoked Potentials ◽

Ex Vivo ◽

Female Rats ◽

Aneurysm Clip ◽

Cord Injury

Abstract Background: Diffusion tensor imaging (DTI) was an effective method to identify subtle changes to normal‐appearing white matter (WM). Here we analyzed the DTI data with other examinations, including motor evoked potentials (MEPs), histopathological images, and behavioral results, to reflect the lesion development in different degrees of spinal cord injury (SCI) in acute and subacute stage. Method: Except for 2 Sprague -Dawley rats died from anesthesia accident, the rest 42 female rats were randomized into 3 groups: control (n=6), moderate group (n=18), and severe group (n=18). Moderate (a 50-g aneurysm clip with 0.4-mm thickness spacer) or severe (a 50-g aneurysm clip with no spacer) contusion SCI at T8 vertebrae were induced. Then the electrophysiological assessments via MEPs, behavioral deterioration via the Basso, Beattie, and Bresnaha (BBB) scores, DTI data, and histopathology examination were analyzed. Results: In this study, we found that the damage of WM myelin, MEPs amplitude, BBB scores and the decreases in values of fractional anisotropy (FA) and axial diffusivity (AD) were more obvious in the severe injury group than that of the moderate group. Additionally, the FA and AD values could identify the extent of SCI in subacute and early acute SCI respectively, reﬂected in the robust correlations with MEPs and BBB scores. While the values of radial diffusivity (RD) showed no significant changes. Conclusions: Our data confirmed that DTI was a valuable in ex vivo imaging tool to identify damaged white matter tracts after graded SCI in rat, which may provide useful information for the early identification of the severity of SCI.

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High Resolution Diffusion Tensor Imaging of Cortical-Subcortical White Matter Tracts in TBI

10.21236/ada513063 ◽

2009 ◽

Author(s):

Deborah M. Little

Keyword(s):

Diffusion Tensor Imaging ◽

White Matter ◽

High Resolution ◽

Diffusion Tensor ◽

Subcortical White Matter ◽

White Matter Tracts

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In vivo diffusion tensor imaging and ex vivo histologic characterization of white matter pathology in a post-status epilepticus model of temporal lobe epilepsy

Epilepsia ◽

10.1111/j.1528-1167.2011.02991.x ◽

2011 ◽

Vol 52 (4) ◽

pp. 841-845 ◽

Cited By ~ 14

Author(s):

Pieter van Eijsden ◽

Wim M. Otte ◽

W. Saskia van der Hel ◽

Onno van Nieuwenhuizen ◽

Rick M. Dijkhuizen ◽

...

Keyword(s):

Diffusion Tensor Imaging ◽

Status Epilepticus ◽

White Matter ◽

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Diffusion Tensor ◽

Ex Vivo ◽

White Matter Pathology

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High-resolution diffusion tensor imaging of fixed brain in a mouse model of Pelizaeus-Merzbacher disease: comparison with quantitative measures of white matter pathology

NMR in Biomedicine ◽

10.1002/nbm.1700 ◽

2011 ◽

Vol 24 (10) ◽

pp. 1369-1379 ◽

Cited By ~ 31

Author(s):

Torsten Ruest ◽

William M. Holmes ◽

Jennifer A. Barrie ◽

Ian R. Griffiths ◽

Thomas J. Anderson ◽

...

Keyword(s):

Diffusion Tensor Imaging ◽

White Matter ◽

High Resolution ◽

Mouse Model ◽

Diffusion Tensor ◽

White Matter Pathology ◽

Pelizaeus Merzbacher Disease

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DTI reveals whole-brain microstructural changes in the P301L mouse model of tauopathy

10.1101/2020.10.28.358465 ◽

2020 ◽

Author(s):

Aidana Massalimova ◽

Ruiqing Ni ◽

Roger M. Nitsch ◽

Marco Reisert ◽

Dominik von Elverfeldt ◽

...

Keyword(s):

White Matter ◽

High Resolution ◽

Mouse Model ◽

Mouse Brain ◽

Diffusion Tensor ◽

Ex Vivo ◽

Brain Regions ◽

Brain Atlas ◽

Microstructural Changes ◽

Allen Mouse Brain Atlas

AbstractIntroductionIncreased expression of hyperphosphorylated tau and the formation of neurofibrillary tangles are associated with neuronal loss and white matter damage. Using high resolution ex vivo diffusion tensor imaging (DTI), we investigated microstructural changes in the white and grey matter in the P301L mouse model of human tauopathy at 8.5 months-of-age. For unbiased computational analysis, we implemented a pipeline for voxel-based analysis (VBA) and atlas-based analysis (ABA) of DTI mouse brain data.MethodsHemizygous and homozygous transgenic P301L mice and non-transgenic littermates were used. DTI data were acquired for generation of fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), axial diffusivity (AD) maps. VBA on the entire brain were performed using SPM8 and SPM Mouse toolbox. Initially, all DTI maps were co-registered with Allen mouse brain atlas to bring them to one common coordinate space. In VBA, co-registered DTI maps were normalized and smoothed in order to perform two-sample t-tests to compare hemizygotes with non-transgenic littermates, homozygotes with non-transgenic littermates, hemizygotes with homozygotes on each DTI parameter map. In ABA, the average values for selected regions-of-interests were computed with co-registered DTI maps and labels in Allen mouse brain atlas. After, the same two-sample t-tests were executed on the estimated average values.ResultsWe made reconstructed DTI data and VBA and ABA pipeline publicly available. With VBA, we found microstructural changes in the white matter in hemizygous P301L mice compared to non-transgenic littermates. In contrast, more pronounced and brain-wide spread changes were observed in VBA when comparing homozygous P301L mice with non-transgenic littermates. Statistical comparison of DTI metrics in selected brain regions by ABA corroborated findings from VBA. FA was found to be decreased in most brain regions, while MD, RD and AD were increased compared to hemizygotes and non-transgenic littermates.Discussion/ConclusionHigh resolution ex vivo DTI demonstrated brain-wide microstructural changes in the P301L mouse model of human tauopathy. The comparison between hemizygous and homozygous P301L mice revealed a gene-dose dependent effect on DTI metrics. The publicly available computational data analysis pipeline can provide a platform for future mechanistic and longitudinal studies.

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