All procedures involving human participants have been performed in compliance with the institutional, national, and international guidelines for human welfare and have been reviewed by the local institutional review board.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 neurological function, b) a positive myelopathy physical examination, and c) magnetic resonance imaging (MRI) evidence of cervical cord compression. NOTE: The exclusion criteria are a) incapability of providing written consent and b) inability to obtain diffusion tensor imaging (DTI) parameters of artifacts. For controls, inclusion criteria are a) no history of significant back or neck injuries, neurological disorders, or spine surgeries; b) no MRI evidence of cervical cord compression.</li><li>Ask each participant to complete and sign a consent form that lists MRI safety guidelines and the imaging protocol. Specifically, patients with chronic spinal cord compression are examined by MRI preoperatively and 1 year postoperatively.</li><li>Provide earplugs for each participant. Place them in a supine position with a head/neck coil enclosing the cervical region, and a landmark at the thyroid cartilage level. Ensure that each participant is in a comfortable position that effectively reduces movement.</li></ol>2. Structural MRI ParametersNOTE: Anatomical T1-weighted (T1 W) images, T2-weighted (T2 W) images, and DTI were acquired on a 3 Tesla MRI scanner with a 16-channel head coil.<ol><li>Use fast perturbation gradient echo (FPGR) for localization scanning to obtain axial, sagittal, and coronal position maps.</li><li>Position the sagittal positioning line with the coronal position maps to ensure that the positioning baseline is parallel to the spinal canal (spinal cord); first locate the sagittal plane T2 W, then copy and paste the sagittal T1 W positioning line to the T2 W positioning line.<ol style='list-style-type:decimal;'><li>Use the following imaging parameters for T1 W and T2 W sagittal imaging: field of view (FOV) = 240 mm x 240 mm, voxel size = 1.0 mm x 0.8 mm x 3.0 mm, slice gap = 0.3 mm, slice thickness = 3 mm, number of excitation (NEX) = 2, fold-over direction = feet/head (FH), and time of echo (TE)/time of repetition (TR) = 10/700 ms (T1 W) and 101/2,500 ms (T2 W). Obtain nine sagittal images covering the entire cervical spinal cord.</li></ol></li><li>Position the axial positioning line on the sagittal T2 W image and cover the intervertebral disc from C2/3 to C6/7, centering on the anteroposterior diameter of the intervertebral space. Use the following imaging parameters: FOV = 180 mm x 180 mm, voxel size = 0.7 mm x 0.6 mm x 3.0 mm, slice thickness = 3 mm, fold-over direction = anterior/posterior (AP), NEX = 2, and TE/TR = 120/3,000 ms.</li><li>Position the axial positioning line on the sagittal T2 W image, centering on the anteroposterior diameter of the intervertebral space, with 45 slices covering the cervical spinal cord from C1 to C7.<ol style='list-style-type:decimal;'><li>Obtain DTI via the following sequence: single-shot spin-echo echo-planar imaging (SE-EPI) with 20 orthogonal directions. Non-coplanar diffusion directions with b-value = 800 s/mm2.</li><li>Use the following imaging parameters: FOV = 230 mm x 230 mm, acquisition matrix = 98 x 98, reconstructed resolution = 1.17 x 1.17, slice thickness = 3 mm, fold-over direction = AP, NEX = 2, EPI factor = 98, and TE/TR = 74/8,300 ms. Provide a time course summarizing the steps in the MRI protocol, as shown in Figure 1. NOTE: The time course summarizing the MRI and DTI protocol is shown in Figure 1.</li></ol></li></ol>

<table><tbody><tr><td>3-Tesla MRI scanner</td><td>Siemens</td><td>40708</td><td>Software: NUMARIS/4</td></tr><tr><td>Syngo MR B17</td><td>Siemens</td><td>40708</td><td>Software: NUMARIS/4</td></tr></tbody></table>

assessing spinal cord compression using diffusion tensor imaging

Source: <a href='https://app.jove.com/v/59069/diffusion-tensor-magnetic-resonance-imaging-chronic-spinal-cord'>Zheng, W. et. al., Diffusion Tensor Magnetic Resonance Imaging in Chronic Spinal Cord Compression. J. Vis. Exp. (2019)</a>This video demonstrates diffusion tensor imaging in assessing chronic spinal cord compression. By analyzing water diffusion patterns, fractional anisotropy, and apparent diffusion coefficient values, the findings reveal axonal damage in compressed regions. The findings provide critical insights into spinal cord pathology and structural integrity.

<figure class="image image_resized image-style-align-center" style="display:table;margin-left:auto;margin-right:auto;width:75%;"><img style="aspect-ratio:700/223;" src="https://cloudfront.jove.com/files/ftp_upload/23575/Figure_1_editor_23575.jpg" alt="MRI scan timeline; chart showing sequence timing for localization, sagittal T2WI, T1WI, axial T2WI, DTI." data-altupdatedat="1762173717000" data-alt="Figure_1.jpg" /></figure>Figure 1: Time course of the clinical MRI protocol. First, the FSPGR sequence was selected for localiza...

Assessing Spinal Cord Compression Using Diffusion Tensor Imaging

Source: Zheng, W. et. al., Diffusion Tensor Magnetic Resonance Imaging in Chronic Spinal Cord Compression. J. Vis. Exp. (2019)This video demonstrates ...

Begin with a human participant positioned inside an MRI scanner.Acquire sagittal and axial images of the cervical spinal cord.Align the axial positioning line with the sagittal image to minimize imaging errors.Next, set the MRI for diffusion tensor imaging to visualize the movement of water molecules.In a healthy spinal cord, water diffusion occurs along the axons, whereas in compressed regions, axonal damage disrupts this directional diffusion.Acquire images and define spherical regions of interest, excluding cerebrospinal fluid, to reduce artifacts.Generate color maps based on fractional anisotropy (FA) values, which indicate the directionality of water diffusion, and the apparent diffusion coefficient (ADC) values, which measure overall diffusion magnitude.Compare these maps of a compressed spinal cord with a healthy one.In the compressed spinal cord, altered FA map patterns in the region of interest indicate axonal damage, while altered ADC map patterns suggest changes in water diffusion, highlighting spinal cord compression.

Before beginning the imaging procedure, provide earplugs to the participant, and help the participant into a comfortable supine position. Place the 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 1 by 0.8 by 3 millimeters, the slice gap to 0.3 millimeters, the slice thickness to 3 millimeters, the number of excitation to 2, the fold over direction to feed 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 T2W image. Next, cover the intervertebral disk 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 3 millimeters, the slice thickness to 3 millimeters, the fold over direction to anterior/posterior, the number of excitation to 2, 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 millimeters 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 3 millimeters, the fold over direction to anterior/posterior, the number of excitation to 2, 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 2-to-1 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 6-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.

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583 Views. Begin with a human participant positioned inside an MRI scanner.Acquire sagittal and axial images of the cervical spinal cord.Align the axial positioning line with the sagittal image to minimize imaging errors.Next, set the MRI for diffusion tensor imaging to visualize the movement of water molecules.In a healthy spinal cord, water diffusion occurs along the axons, whereas in compressed regions, axonal damage disrupts this directional diffusion.Acquire image...

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<figure class="image image_resized image-style-align-center" style="display:table;margin-left:auto;margin-right:auto;width:75%;"><img title="figure-results-1" style="aspect-ratio:700/223;" src="https://cloudfront.jove.com/files/ftp_upload/23575/Figure_1_editor_23575.jpg" alt="MRI scan timeline; chart showing sequence timing for localization, sagittal T2WI, T1WI, axial T2WI, DTI." data-altupdatedat="1762173717000" data-alt="Figure_1.jpg" /></figure>Figure 1: Time course of the clinical MRI protocol. First, the FSPGR sequence was selected for localiza...

Assessing Spinal Cord Compression Using Diffusion Tensor Imaging

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