Back to Search
Start Over
Quantification of Myelinated Nerve Fraction and Degeneration in Spinal Cord Neuropil by SHIFT MRI
- Source :
- Scopus, Repositório Institucional da UNESP, Universidade Estadual Paulista (UNESP), instacron:UNESP
- Publication Year :
- 2020
-
Abstract
- Made available in DSpace on 2021-06-25T10:13:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Background: Neurodegeneration is a complex cellular process linked to prompt changes in myelin integrity and gradual neuron loss. Current imaging techniques offer estimations of myelin volumes in lesions/remyelinated areas but are limited to detect subtle injury. Purpose: To investigate whether measurements detected by a signal hierarchically isolated as a function of time-to-echo (SHIFT) MRI technique can determine changes in myelin integrity and fiber axolemma. Study Type: Prospective animal model. Animal Model: Surgically demyelinated spinal cord (SC) injury model in rodents (n = 6). Field Strength/Sequence: Gradient-echo spin-echo at 3T. Assessment: Multicompartment T2 relaxations were computed by SHIFT MRI in 75-microns-resolution images of the SC injury penumbra region 2 weeks post-trauma. G-ratio and axolemma delamination were assessed by transmission electron microscopy (TEM) in intact and injured samples. SC myelinated nerve fraction was computed by SHIFT MRI prospectively and assessed histologically. Statistical Tests: Relations between SHIFT-isolated T2-components and TEM measurements were studied using linear regression and t-tests. Pearson's correlation and significance were computed to determine the SHIFT's sensitivity to detect myelinated fibers ratio in gray matter. Regularized least-squares-based ranking analysis was employed to determine SHIFT MRI's ability to discern intact and injured myelinated nerves. Results: Biexponential signals isolated by SHIFT MRI for intact vs. lesion penumbra exhibited changes in T2, shifting from intermediate components (25 ± 2 msec) to long (43 ± 11 msec) in white matter, and similarly in gray matter regions-of-interest (31 ± 2 to 46 ± 16 msec). These changes correlated highly with TEM g-ratio and axon delamination measurements (P < 0.05). Changes in short T2 components were observed but not statistically significant (8.5 ± 0.5 to 7 ± 3 msec, P = 0.445, and 4.0 ± 0.9 to 7 ± 3 msec, P = 0.075, respectively). SHIFT MRI's ability to detect myelinated fibers within gray matter was confirmed (P < 0.001). Data Conclusion: Changes detected by SHIFT MRI are associated with abnormal intermembrane spaces formed upon mild injury, directly correlated with early neuro integrity loss. Level of Evidence 1. Technical Efficacy Stage 2. Center for Neuroregneration Department of Neurosurgery Houston Methodist Research Institute Houston Methodist Hospital Department of Biological Physics Universidade Estadual Paulista UNESP Division of Arts and Sciences NYU Shanghai NYU-ECNU Institute of Cognitive Neuroscience at NYU Shanghai Center for Neural Science and Department of Psychology New York University Department of Biological Physics Universidade Estadual Paulista UNESP
- Subjects :
- Neuropil
quantitative MRI
030218 nuclear medicine & medical imaging
Lesion
White matter
03 medical and health sciences
Myelin
0302 clinical medicine
Nuclear magnetic resonance
medicine
Animals
Radiology, Nuclear Medicine and imaging
Prospective Studies
Axon
Spinal cord injury
Myelin Sheath
Spinal Cord Injuries
rat spinal cord
mild neuro injury
Chemistry
Penumbra
neurodegeneration
medicine.disease
Spinal cord
Magnetic Resonance Imaging
spinal cord injury
Axolemma
medicine.anatomical_structure
Spinal Cord
T2 relaxation
medicine.symptom
Subjects
Details
- ISSN :
- 15222586
- Volume :
- 53
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- Journal of magnetic resonance imaging : JMRIReferences
- Accession number :
- edsair.doi.dedup.....936ba2ab9fa6c98384ad6ce4c38843ff