Evaluating the reliability of computed tomography for the diagnosis of intervertebral disc extrusion in dogs



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PICO question

In dogs with an acute thoracolumbar myelopathy, is non-contrast computed tomography (CT) a reliable method for the diagnosis of intervertebral disc extrusion, compared to magnetic resonance imaging (MRI)?


Clinical bottom line

Category of research question


The number and type of study designs reviewed

Four papers were critically reviewed. Two were retrospective, cross-sectional studies, and two were prospective, observational cohort studies

Strength of evidence


Outcomes reported

The current literature suggests that CT is often sufficient for the diagnosis of thoracolumbar intervertebral disc extrusion, with MRI superior to CT for lesion characterisation. Non-contrast CT is likely sufficient for the diagnosis and surgical planning for intervertebral disc disease in Dachshunds. However, MRI is recommended for diagnosis and surgical planning of thoracolumbar intervertebral disc disease in non-Dachshund breeds


Computed tomography is often sufficient for the diagnosis of thoracolumbar intervertebral disc extrusion. However, MRI is superior to CT for lesion characterisation and it is therefore recommended to use MRI for cases requiring surgical planning. Computed tomography is likely sufficient for the diagnosis and surgical planning of intervertebral disc disease in Dachshunds

Regard for the reason of diagnostics performed (e.g. surgical planning) and the likelihood of other differential diagnoses (e.g. spinal neoplasms) should be taken before deciding to use one imaging modality over the other. Consideration into the risks associated with anaesthetising an animal with a spinal cord lesion, the ability of the practitioner to accurately localise the myelopathy and interpret the results, should be taken before pursuing diagnostics in these cases


How to apply this evidence in practice

The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.

Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.


Open Access Peer Reviewed


Cooper, J.J., Young, B.D., Griffin IV, J.F., Fosgate, G.T. & Levine, J.M. (2014). Comparison between noncontrast computed tomography and magnetic resonance imaging for detection and characterization of thoracolumbar myelopathy caused by intervertebral disk herniation in dogs. Veterinary Radiology & Ultrasound. 55(2), 182–189. DOI: http://dx.doi.org/ 10.1111/vru.12114

Emery, L., Hecht, S. & Sun, X. (2018). Investigation of parameters predicting the need for diagnostic imaging beyond computed tomography in the evaluation of dogs with thoracolumbar myelopathy: Retrospective evaluation of 555 dogs. Veterinary Radiology & Ultrasound. 59(2), 147–154. DOI: https://doi.org/10.1111/vru.12576

Noyes, J. A., Thomovsky, S.A., Chen, A.V., Owen, T.J., Fransson, B.A., Carbonneau, K.J. & Matthew, S.M. (2017). Magnetic resonance imaging versus computed tomography to plan hemilaminectomies in chondrodystrophic dogs with intervertebral disc extrusion. Veterinary Surgery. 46(7), 1025–1031. DOI: https://doi.org/10.1111/vsu.12700

Tamura, S., Doi, S., Tamura, Y., Takahashi, K., Enomoto, H., Ozawa, T. & Uchida, K. (2015). Thoracolumbar intradural disc herniation in eight dogs: clinical, low-field magnetic resonance imaging, and computed tomographic myelography findings. Veterinary Radiology & Ultrasound. 56(2), 160–167. DOI: https://doi.org/10.1111/vru.12213

Vol. 6 No. 4 (2021): The fourth issue of 2021

Section: Knowledge Summaries

Categories :  Small Animal  /  Dogs  /  Cats  /  Rabbits  /  Production Animal  /  Cattle  /  Sheep  /  Pig  /  Equine  /  Exotics  /