J Vet Sci.  2010 Mar;11(1):73-79. 10.4142/jvs.2010.11.1.73.

Computed tomographic characteristics of acute thoracolumbar intervertebral disc disease in dogs

• Lim C
• Kweon OK
• Choi MC
• Choi J
• Yoon J

• KMID: 1106160
• DOI: http://doi.org/10.4142/jvs.2010.11.1.73

Abstract

Forty canine patients with a presumptive diagnosis of the intervertebral disc herniation at the thoracolumbar region were imaged. A neurological examination was performed and all patients were classified under four grades by the examination. The degrees of attenuation of the herniated disc material were measured in Housefield units (HU) in each image. The ratio of the area to herniated disc material and the height to disc material were measured. The clinical grade was correlated with the area ratio of the herniated disc material to the spinal cord, but not correlated with the height ratio of that. In the patients with epidural hemorrhage at surgery, HUs of the herniated disc material was lower than those with no epidural hemorrhage at surgery. Non-contrast computed tomography scans of the spine can be useful in diagnosing acute intervertebral disc disease in chondrodystrophoid breeds, evaluating patient status and identifying concurrent epidural hemorrhage.

Keyword

area; CT; dog; epidural hemorrhage; intervertebral disc disease

MeSH Terms

Animals
Dog Diseases/*pathology/radiography
Dogs
Intervertebral Disk Displacement/radiography/*veterinary
Lumbar Vertebrae/*pathology/radiography
Retrospective Studies
Thoracic Vertebrae/*pathology/radiography
Tomography, X-Ray Computed/methods/standards/*veterinary

Figure

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  Fig. 1 Location of disc herniation. The central (A), dorsal (B), left lateral (C), and right lateral (D) locations of disc herniation.

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  Fig. 2 Measurements for the index calculation with vertebra window (A) and spine window (B). 'a' represents the area of spinal canal and 'b' the area of herniated disc material, line 'cd' the height of spinal canal and line 'e-f' the height of herniated disc material. The formula for A-index calculation is b/a ×100 (%), and for H-index calculation (e to f / c to d) ×100 (%).

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  Fig. 3 Measurement of the HU of herniated disc materials. The solid line shows the total herniated disc area and the dotted line the region of interest of non-mineralized disc area.

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  Fig. 4 Mean A-index in relation to the grade by three different method of sampling (top, average of top 3 and average of top 5).

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  Fig. 5 Mean H-index in relation to the grade by three different methods of sampling (top, average of top 3 and average of top 5).

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