• 1. Chang Y, Dennis R, Platt SR, et al. Magnetic resonance imaging of traumatic intervertebral disc extrusion in dogs. Vet Rec 2007; 160:795799.

    • Search Google Scholar
    • Export Citation
  • 2. De Risio L, Adams V, Dennis R, et al. Association of clinical and magnetic resonance imaging findings with outcome in dogs with presumptive acute noncompressive nucleus pulposus extrusion: 42 cases (2000–2007). /Am Vet Med Assoc 2009; 234:495504.

    • Search Google Scholar
    • Export Citation
  • 3. De Risio L, Adams V, Dennis R, et al. Magnetic resonance imaging findings and clinical associations in 52 dogs with suspected ischemic myelopathy. J Vet Intern Med 2007; 21:12901298.

    • Search Google Scholar
    • Export Citation
  • 4. Abramson CJ, Garosi L, Platt SR, et al. Magnetic resonance imaging appearance of suspected ischemic myelopathy in dogs. Vet Radiol Ultrasound 2005; 46:225229.

    • Search Google Scholar
    • Export Citation
  • 5. De Risio L, Platt S. Fibrocartilaginous embolic myelopathy in small animals. Vet Clin North Am Small Anim Pract 2010; 40:859869.

  • 6. Cauzinille L. Fibrocartilaginous embolism in dogs. Vet Clin North Am Small Anim Pract 2000; 30:155167.

  • 7. D'Anjou MA, Carmel EN, Tidwell AS. Value of fat suppression in gadolinium-enhanced magnetic resonance neuroimaging. Vet Radiol Ultrasound 2011; 52:S85S90.

    • Search Google Scholar
    • Export Citation
  • 8. Byrt T. How good is that agreement? Epidemiology 1996; 7:561.

  • 9. Ford LT, Gilula LA, Murphy WA, et al. Analysis of gas in vacuum lumbar disc. AJR Am J Roentgenol 1977; 128:10561057.

  • 10. Müller MK, Ludewig E, Oechtering G, et al. The vacuum phenomenon in intervertebral disc disease of dogs on computed tomography images. J Small Anim Pract 2013; 54:253257.

    • Search Google Scholar
    • Export Citation
  • 11. Seiler GS, Robertson ID, Mai W, et al. Usefulness of a half-fourier acquisition single-shot turbo spin-echo pulse sequence in identifying arachnoid diverticula in dogs. Vet Radiol Ultrasound 2012; 53:157161.

    • Search Google Scholar
    • Export Citation
  • 12. An HS, Nguyen C, Haughton VM, et al. Gadolinium-enhancement characteristics of magnetic resonance imaging in distinguishing herniated intervertebral disc versus scar in dogs. Spine 1994; 19:20892095.

    • Search Google Scholar
    • Export Citation
  • 13. Suran JN, Durham A, Mai W, et al. Contrast enhancement of extradural compressive material on magnetic resonance imaging. Vet Radiol Ultrasound 2011; 52:1016.

    • Search Google Scholar
    • Export Citation
  • 14. Simonson TM, Yuh WT. Stroke and cerebral ischemia. In: Edelman RR, Zlatkin MB, Hesselink JR, eds. MRI clinical magnetic resonance imaging. Vol. 1. 2nd ed. Philadelphia: WB Saunders Co, 1996;767786.

    • Search Google Scholar
    • Export Citation
  • 15. McConnell JF, Garosi LS. Intramedullary intervertebral disk extrusion in a cat. Vet Radiol Ultrasound 2004; 45:327330.

  • 16. Kent M, Holmes S, Cohen E, et al. Imaging diagnosis—CT myelography in a dog with intramedullary intervertebral disc herniation. Vet Radiol Ultrasound 2011; 52:185187.

    • Search Google Scholar
    • Export Citation
  • 17. Sanders SG, Bagley RS, Patrick RG. Intramedullary spinal cord damage associated with intervertebral disk material in a dog. J Am Vet Med Assoc 2002; 221:15941596.

    • Search Google Scholar
    • Export Citation
  • 18. Evans H, de Lahunta A. The Skeleton. In: Evans H, de Lahunta A, eds. Miller's anatomy of the dog. 4th ed. St Louis: Elsevier, 2013;80184.

    • Search Google Scholar
    • Export Citation
  • 19. Aultman CD, Scannel J, McGill SM. The direction of progressive herniation in porcine spine motion segments is influenced by the orientation of the bending axis. Clin Biomech (Bristol, Avon) 2005; 20:126129.

    • Search Google Scholar
    • Export Citation

Advertisement

Assessment of interobserver agreement and use of selected magnetic resonance imaging variables for differentiation of acute noncompressive nucleus pulposus extrusion and ischemic myelopathy in dogs

Swan Specchi DVM, PhD1, Philippa Johnson DVM2, Guy Beauchamp PhD3, Isabelle Masseau DVM, PhD4, and Pascaline Pey DVM, PhD5
View More View Less
  • 1 Department of Clinical Sciences, Faculté de Médecine Vétérinaire, Université de Montréal, St Hyacinthe, QC, Canada J2S 7C6.
  • | 2 Department of Medical Imaging, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.
  • | 3 Department of Clinical Sciences, Faculté de Médecine Vétérinaire, Université de Montréal, St Hyacinthe, QC, Canada J2S 7C6.
  • | 4 Departments of Veterinary Medicine & Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65211.
  • | 5 Department of Clinical Sciences, Faculté de Médecine Vétérinaire, Université de Montréal, St Hyacinthe, QC, Canada J2S 7C6.

Abstract

OBJECTIVE To evaluate interobserver agreement for features used in presumptive diagnosis of acute noncompressive nucleus pulposus extrusion (ANNPE) or ischemic myelopathy by MRI, compare findings on postcontrast T1-weighted (T1W) MRI sequences with fat saturation (FS) for the 2 conditions, and determine whether length and directional patterns of hyperintensity of the intramedullary spinal cord on T2-weighted (T2W) fast spin echo (FSE) MRI sequences differ between dogs with these diseases.

DESIGN Retrospective, observational study.

ANIMALS 20 dogs with clinical signs compatible with ANNPE (n = 14) or ischemic myelopathy (6).

PROCEDURES 3 observers evaluated MRI data (including T2W FSE, T2W single-shot FSE, and T1W FS sequences) for dogs with a presumptive diagnosis of ischemic myelopathy or ANNPE. Interobserver agreement for variables of interest including presumptive diagnosis was assessed by κ statistic calculations. Associations between diagnosis and variables of interest were assessed with Fisher exact or Cochran-Mantel-Haenszel tests.

RESULTS Perfect interobserver agreement (κ = 1 for all comparisons) was found for the presumptive diagnosis of ischemic myelopathy versus ANNPE. Meningeal enhancement on postcontrast T1W FS MRI images and nonlongitudinal directional pattern of intramedullary hyperintensity on T2W FSE images were significantly associated with a diagnosis of ANNPE. Greater length of intramedullary hyperintensity was significantly associated with a diagnosis of ischemic myelopathy.

CONCLUSIONS AND CLINICAL RELEVANCE Directional pattern and length of intramedullary hyperintensity on T2W FSE MRI images and enhancement patterns in postcontrast T1W FS sequences may provide important contributions to the criteria currently used in the presumptive diagnosis of ischemic myelopathy versus ANNPE.

Contributor Notes

Dr. Specchi's present address is Diagnostic Imaging Service, Istituto Veterinario di Novara, Granozzo con Monticello, Italy, 28060.

Dr. Johnson's present address is College of Veterinary Medicine, Cornell University, Ithaca, NY 14853.

Dr. Pey's present address is Medical Imaging Department, Université Paris-Est Créteil, Ecole Nationale Vétérinaire d'Alfort, 94704 Maisons-Alfort Cedex, France.

Address correspondence to Dr. Specchi (swan.specchi.rad@gmail.com).