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Dynamic imaging of the cervical spine may be warranted in order to evaluate the extension of a disc compression versus the presence of “Wobblers Disease” or facet hypertrophy. Similar to lumbo-sacral dynamic imaging, extending the neck can allow you to appreciate dynamic changes to the compression of the spinal cord. Dynamic imaging will be added as additional sequences after your normal imaging study. Typically this is accomplished with myelographic, T2 sagittal, and T2 axial dynamic images. It is usually ideal to perform pre and post imaging prior to dynamic changes in order for the pre and post images to match.

There are multiple ways to perform dynamic imaging of the cervical spine and they all come with certain risks. Any dynamic imaging should be performed under the direct supervision of a doctor. The first method is hyperextension with a bolster. In this method, with the patient in dorsal recumbency, place…

The brachial plexus is an area of the central nervous system where the peripheral nerves branch off of the spinal cord and extend out to the forelimbs. The brachial plexus extends from the level of C4 to T3 cranially and caudally, laterally through the axilla and shoulder girdle, and ventro dorsally from the posterior aspects of the spinous processes through the anterior portion of the shoulder.

Imaging sequences should be performed with a large FOV and enough additional slices to cover that entire area. It is usually easiest to begin with a coronal STIR or T2 fat saturated sequence covering the entire area in order to help locate any abnormalities and focus the subsequent imaging sequences.

The purpose of the study is to evaluate for nerve sheath lesions in the brachial plexus that can cause muscle atrophy, weakness, and proprioception deficits in the forelimbs.

Coronal slice group positioning

Axial slice…

In the case where your patient is suspected to have an Occipital-Atlanto (base of the skull - C1) or Atlanto-Axial (C1-C2) instability it may be necessary to perform and "OAA" volume study to evaluate for edema in and around the communications between the occipital bone, the atlas (C1), and the axis (C2). On MRI this is performed by utilizing a T2 weighted 3D volumetric sequence. These images show how to position the volume scan and what the volume image should look like when it is finished.

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The image at the top is a 3D reconstructed volume rendering of a CT scan of the OAA. On this image there is a red arrow pointing to a fractured dens (odontoid process) of C2. Imaging this are should be performed with very thin slices on CT. Be very careful when moving and positioning a patient suspected of an atlanto-axial subluxation or fracture.…

The lumbo-sacral plexus is the region of the caudal spine where the peripheral nerves branch off of the spinal cord and extend into the hind limbs. Imaging of this area should include a larger field of view and enough slices to cover the entire region. The plexus covers and area from L4 to S3 and extends laterally through the hips. The majority of the primary branches of the plexus only extend out as far as the lateral margins of the pelvis. It is best to start with a large Coronal STIR or T2 fat saturated sequence that covers all of the anatomy to help narrow down the focus for the rest of the study.

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Additional imaging of the plexus may include a "Double Oblique" T2 weighted sequence in order to acquire a true cross section of the sciatic nerve. As you can see in the image below the sagittal…

Sometimes it will be necessary to perform a dynamic imaging study on the lumbo-sacral junction in order to determine if a compressive L7-S1 disk requires surgical intervention and specifically a L/S fusion.

You should already be performing your routine MRI of the lumbar spine with the patient in a "hyperextended" position with their lower limb extended and secured away from their body. This position will force the L7-S1 disk into the most extreme amount of herniation and compression for the best visualization. As a result of this positioning the patient may experience some heightened discomfort and additional anesthetic intervention will like be necessary in order to keep the patient comfortable and asleep.

Once you've determined if the L/S disk is causing a significant compression we want to determine wether or not the disk is "dynamic" in nature. Meaning does it move in and out of the disk space with flexion…

Welcome to the VIRA Forum. This is a place for anyone in veterinary imaging to offer support to our colleagues. I'm sure we're all aware that veterinary imaging is a lawless land without much guidance, information, or regulation. That's nice in a way because it gives us the freedom to explore and grow, but it also leaves us alone with a lot of questions and not enough support to feel like we're doing a good job. I want this to be a safe space where imaging technologists can come together, build a community, and help raise the standards of what veterinary imaging could be.

Thank you for visiting and for being a part of our community.

Enjoy!

- Kevin Stevens, RT,R,MR