This study was supported by Guangzhou Science and Technology Project of China (No. 201607010021) and the Nature Science Foundation of JiangXi (No. 20142BAB205065)

The study was approved by the local Medical Ethics Committee in Guangzhou First People&#8217;s Hospital in China. Signed informed consent forms were received from healthy volunteers and participants prior to participation. All of the studies were conducted in accordance with the World Medical Association Declaration of Helsinki.
1. Subject Preparation
<ol>
	<li>Ensure that each participant meets the following criteria for chronic spinal cord compression: a) a history of loss of significant n...

<ol>
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A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systematic+review+of+magnetic+resonance+imaging+characteristics+that+affect+treatment+decision+making+and+predict+clinical+outcome+in+patients+with+cervical+spondylotic+myelopathy.">Systematic review of magnetic resonance imaging characteristics that affect treatment decision making and predict clinical outcome in patients with cervical spondylotic myelopathy.</a> Spine. 38 (22 Suppl 1), S89 (2013).</li><li>Nouri, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Role of Magnetic Resonance Imaging in Predicting Surgical Outcome in Patients with Degenerative Cervical Myelopathy. , (2015).</li><li>Chen, C. J., Lyu, R. K., Lee, S. T., Wong, Y. C., Wang, L. 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A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=DTI+for+assessing+axonal+integrity+after+contusive+spinal+cord+injury+and+transplantation+of+oligodendrocyte+progenitor+cells.">DTI for assessing axonal integrity after contusive spinal cord injury and transplantation of oligodendrocyte progenitor cells.</a> Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society. 2012 (4), 82-85 (2012).</li><li>Lewis, M., Yap, P. 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G., Cen, S. Y., Lebel, R. M., Hsieh, P. C., Law, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diffusion+Tensor+Imaging+Correlates+with+the+Clinical+Assessment+of+Disease+Severity+in+Cervical+Spondylotic+Myelopathy+and+Predicts+Outcome+following+Surgery.">Diffusion Tensor Imaging Correlates with the Clinical Assessment of Disease Severity in Cervical Spondylotic Myelopathy and Predicts Outcome following Surgery.</a> American Journal of Neuroradiology. 34 (2), 471-478 (2013).</li><li>Kerkovsk&#253;, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+resonance+diffusion+tensor+imaging+in+patients+with+cervical+spondylotic+spinal+cord+compression:+correlations+between+clinical+and+electrophysiological+findings.">Magnetic resonance diffusion tensor imaging in patients with cervical spondylotic spinal cord compression: correlations between clinical and electrophysiological findings.</a> Spine. 37 (1), 48-56 (2012).</li><li>Zheng, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+Diffusion+Tensor+Imaging+Cutoff+Value+to+Evaluate+the+Severity+and+Postoperative+Neurologic+Recovery+of+Cervical+Spondylotic+Myelopathy.">Application of Diffusion Tensor Imaging Cutoff Value to Evaluate the Severity and Postoperative Neurologic Recovery of Cervical Spondylotic Myelopathy.</a> World Neurosurgery. 118, e849-e855 (2018).</li><li>Thurnher, M. 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Conventional MRI is usually utilized to assess the prognosis of patients with various spine conditions. However, this imaging modality provides macroscopic anatomic detail rather than microstructure evaluation14, which limits the prediction of neurological function. Furthermore, traditional MRI may underestimate the severity and extent of spinal cord damage. The emergence of DTI can help surgeons to evaluate spinal cord function more accurately by providing quantitative information on water molecu...

Chronic spinal cord compression is the most common cause of spinal cord impairment1. This condition can be due to posterior longitudinal ligament ossification, hematoma, cervical disc herniation, vertebral degeneration, or intraspinal tumors2,3. Chronic spinal cord compression can lead to various degrees of functional deficits; however, there are clinical cases with serious spinal cord compression without any neurological symptoms and signs, as well as patients with mild spinal cord compression but serious neurological deficits4. Under these circumstances, sensitive imaging is essential to evaluate compression severity and identify the range of damage.
Conventional MRI plays a significant role in elucidating spinal cord anatomy. This technique is usually utilized to evaluate the compression degree because of its sensitivity to soft tissues5. Many parameters can be measured from MRI, such as MR signal intensity, cord morphology, and spinal canal area. However, MRI has some limitations and only provides qualitative information rather than quantitative results6. Patients with chronic spinal cord compression often have abnormal signal changes of MRI intensity. However, discrepancies between clinical symptoms and MRI intensity changes make it hard to diagnose a functional condition based solely on MRI characteristics7. Previous studies highlight this controversy in terms of the prognostic value of MRI T2 hyperintensity in the spinal cord8. Two groups reported that T2 hyperintensity of the spinal cord is a poor prognostic parameter after surgery for chronic spinal cord compression8,9. In contrast, some authors found no significant association between T2 signal changes and prognosis8,9. Chen et al. and Vedantam et al. divided MRI T2 hyperintensities into two categories corresponding to different prognostic outcomes10,11. Type 1 showed faint, fuzzy, indistinct borders, and this category demonstrated reversible histologic changes. Type 2 images presented intense, well-defined borders, which corresponded to irreversible pathologic damage. Conventional T1/T2 MRI techniques do not provide adequate information to identify these two categories and evaluate patient prognosis. By contrast, DTI, a more sophisticated imaging technique, may help obtain more specific prognostic information by quantitatively detecting microstructural changes in tissues via water molecule diffusion.
In recent years, DTI has garnered increasing attention due to its ability to describe spinal cord microarchitecture. DTI can measure the direction and magnitude of water molecule diffusion in tissues. DTI parameters can quantitatively evaluate neural damage in patients with chronic spinal cord compression. FA and the ADC are the most commonly applied parameters during spinal cord evaluation. The FA value reveals the degree of anisotropy to orientate surrounding axonal fibers and describe anatomic boundaries12,13. The ADC value provides information on the characteristics of molecular motion in many directions in a three-dimensional space and reveals the mean of diffusivities along the three principal axes6,12. Changes in these parameters are associated with microstructural alterations that influence water molecule diffusion. Therefore, surgeons can utilize/measure DTI parameters to identify spinal cord pathology. The present study provides DTI methods and processes that provide more detailed prognostic information to treat patients with chronic spinal cord compression.

<table border="0" cellpadding="0" cellspacing="0" style="width:849px;" width="849">
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">3-Tesla MRI scanner</td>
			<td style="width:123px;">Siemens</td>
			<td align="right" style="width:344px;">40708</td>
			<td style="width:167px;">Software: NUMARIS/4</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Syngo MR B17</td>
			<td>Siemens</td>
			<td align="right">40708</td>
			<td>Software: NUMARIS/4</td>
		</tr>
	</tbody>
</table>

diffusion tensor magnetic resonance imaging in chronic spinal cord compression

Chronic spinal cord compression is the most common cause of spinal cord impairment in patients with nontraumatic spinal cord damage. Conventional magnetic resonance imaging (MRI) plays an important role in both confirming the diagnosis and evaluating the degree of compression. However, the anatomical detail provided by conventional MRI is not sufficient to accurately estimate neuronal damage and/or assess the possibility of neuronal recovery in chronic spinal cord compression patients. In contrast, diffusion tensor imaging (DTI) can provide quantitative results according to the detection of water molecule diffusion in tissues. In the present study, we develop a methodological framework to illustrate the application of DTI in chronic spinal cord compression disease. DTI fractional anisotropy (FA), apparent diffusion coefficients (ADCs), and eigenvector values are useful for visualizing microstructural pathological changes in the spinal cord. Decreased FA and increases in ADCs and eigenvector values were observed in chronic spinal cord compression patients compared to healthy controls. DTI could help surgeons understand spinal cord injury severity and provide important information regarding prognosis and neural functional recovery. In conclusion, this protocol provides a sensitive, detailed, and noninvasive tool to evaluate spinal cord compression.

This is a summary of results obtained from healthy volunteers and patients with cervical spondylotic myelopathy. The protocol enabled the physician to view DTI maps. This technology could serve as an objective measure to measure functional status in myelopathic conditions. DTI maps of healthy volunteers are shown in Figure 3. The DTI parameters of healthy volunteers were as follows: FA = 0.661; ADC = 1.006 x 10-3 mm2/s; E1 = 1.893 x 10-3 mm2/s; E2 ...

Watch this Scientific Journal Video about Diffusion Tensor Magnetic Resonance Imaging in Chronic Spinal Cord Compression at JoVE.com

Diffusion Tensor Magnetic Resonance Imaging in Chronic Spinal Cord Compression

Here, we present a protocol for the application of diffusion tensor imaging parameters to evaluate spinal cord compression.

Chronic spinal cord compression is the most common cause of spinal cord impairment in patients with nontraumatic spinal cord damage. Conventional magnetic ...

The anatomical spinal cord microstructure detail provided by conventional MRI does not accurately estimate the actual neuronal damage or the neuronal recovery potential in chronic spinal cord compression patients. Diffusion tensor imaging, or DTI, may help us to obtain more specific prognostic information by detecting quantity microstructure change in tissues via the diffusion of water molecules. Chronic spinal cord compression can cause recurrent ischemic damage to the spine cord, resulting in histopathological change in downstream nerve fibers.This change can be visualized with the DTI. DTI is a sensitive technique that can provide a measure of direction and the diffusion magnitude of water molecules in tissues. Here, we demonstrate the application of diffusion tensor imaging parameters in the evaluation of compressed spinal cord for use in high-performance clinical MRI scanners operating a 3.0T MR system.Before beginning the imaging procedure, provide earplugs to the participant and help the participant into a comfortable supine position. Place a head/neck coil over the cervical region and a landmark at the thyroid cartilage level. When the participant is in position, use fast perturbation gradient echo to obtain axial, sagittal, and coronal position maps.Locate the T2-weighted sagittal plane, and copy and paste the sagittal T1-weighted positioning line to the T2-weighted positioning line using the coronal position maps to ensure that the positioning baseline is parallel to the spinal canal. Set the T1-and T2-weighted field of view to 240 by 240 millimeters, the voxel size to one by 0.8 by three millimeters, the slice gap to 0.3 millimeters, the slice thickness to three millimeters, the number of excitation to two, the fold-over direction to feet-head, the time of echo of repetition to 10 over 700 milliseconds for the T1-weighted field, and 101 over 2, 500 for the T2-weighted field. Then, obtain nine sagittal images covering the entire cervical spinal cord, and position the axial positioning line on the sagittal T2 W image.Next, cover the intervertebral disc from C2-3 to C6-7, centering on the anteroposterior diameter of the intervertebral space, and set the field of view to 180 by 180 millimeters, the voxel size to 0.7 by 0.6 by three millimeters, the slice thickness to three millimeters, the fold-over direction to anterior-posterior, the number of excitation to two, and the time of echo time of repetition to 120 over 3, 000 milliseconds. Then, position the axial positioning line on the sagittal T2-weighted image, centering on the anteroposterior diameter of the intervertebral space, with 45 slices covering the cervical spinal cord from C1 to C7.To obtain diffusion tensor imaging, use single-shot spin-echo echo-planar imaging with 20 orthogonal directions and non-coplanar diffusion directions with b-values equal to 800 seconds per millimeter squared, and set the field of view to 230 by 230 millimeters, the acquisition matrix to 98 by 98, the reconstructed resolution to 1.17 by 1.17, the slice thickness to three millimeters, the fold-over direction to anterior-posterior, the number of excitation to two, the echo-planar imaging factor to 98, and the time of echo time of repetition to 74 over 8, 300 milliseconds. For image post-processing, export the images to the analyzer, and load the T2-weighted sagittal and axial images of the intervertebral space into the filming interface.Locate the most compressed portion of the cervical spinal cord, and load the fractional anisotropy image in the two-to-one viewing interface. Click Position Display Series, and determine the level of highest compression from the top to the bottom of the location map. Click File to select the tensor image.Select Neuro 3D Magnetic Resonance to automatically create apparent diffusion coefficient and fractional anisotropy color maps. Advance to the side of the highest compression, and use the Start Evaluation Mode to create spherical six-millimeter cubed regions of interest in and around the inner spinal cord to exclude the partial volume effects of cerebrospinal fluid. The fractional anisotropy and apparent diffusion coefficient values will be calculated automatically.Then, click Diffusion and select E1, E2, and E3 to display their values. Here, representative diffusion tensor imaging maps from healthy volunteers are shown. These diffusion tensor imaging maps from chronic spinal cord compression patients allows the functional status of the compression in these patients to be measured as just demonstrated.Post-operative imaging of chronic spinal cord compression patients who underwent surgery allows a functional assessment of the alleviation of the compression to help track patient recovery. Regions of interest must be draw at the inner spinal cord to exclude the partial volume effects of the cerebrospinal fluids. The quantitative data obtained by DTI allows an accurate judgment of the extent of the lesion damage and provides timely and accurate objective indications for clinic treatment.Before scanning, we ask each participant to fill out and sign a consent form that outlines the imaging protocol and MRI safety guidelines.

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Research

JoVE Journal

Neuroscience

8.7K visualizações.  Guangzhou Medical University. O detalhe da microestrutura da medula espinhal anatômica fornecida pela ressonância magnética convencional não estima com precisão o dano neuronal real ou o potencial de recuperação neuronal em pacientes crônicos de compressão medular. A imagem do tensor de difusão, ou DTI, pode nos ajudar a obter informações mais específicas do prognóstico, detectando a alteração da microestrutura da quantidade nos tecidos através da difusão de moléculas de água. A compressão da medula e...