THE COMPUTED TOMOGRAPHIC APPEARANCE OF ACUTE THORACOLUMBAR INTERVERTEBRAL DISC HERNIATIONS IN DOGS

Authors

  • Natasha J. Olby Vet MB, PhD,

    Corresponding author
    1. Department of Clinical Sciences, Physiological Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606.
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  • Karen R. Müntana DVM, MS,

    1. Department of Clinical Sciences, Physiological Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606.
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  • Nicholas J.H. Sharp BVM, PhD,

    1. Department of Clinical Sciences, Physiological Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606.
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  • Donald E. Thrall DVM, PhD

    1. Department of Anatomy, Physiological Sciences, and Radiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606.
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  • Support provided by College of Veterinary Medicine, North Carolina State University State Research Funds, American Kennel Club.

Address correspondence and reprint requests to Dr. Natasha Olby, College of Veterinary Medicine, North Carolina State University, 4700 Hills borough Street, Raleigh, NC 27606.

Abstract

The appearance of herniated intervertebral disc material in the thoracolumbar vertebral canal was evaluated in 23 dogs using computed tomography (CT). The images were then compared with the myelographic and surgical findings. The normal spinal cord, outlined by epidural fat over intervertebra1 disc spaces, was of intermediate attenuation on transverse CT images. Herniated disc material was identified in all animals as a heterogeneous hyperattenuating extradural mass. The attenuation of the disc material increased with the degree of mineralization. In seven dogs, the herniated material was only slightly more attenuating than the spinal cord. In these dogs, small fragments of mineralized disc material and significant hemorrhage were found in the epidural space at surgery. In dogs with a long standing history of disc herniations, disc material identified in the vertebral canal had a more hyperattenuating and homogeneous appearance than recently herniated disc material. We conclude that mineralized, herniated disc material and hemorrhage can be identified quickly and safely in dogs using CT.

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