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Evaluation of agreement and correlation of results obtained with MRI-based and macroscopic observation-based grading schemes when used to assess intervertebral disk degeneration in cats

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  • 1 1Neurology Service, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland.
  • | 2 2Departments of Small Animal Surgery, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland.
  • | 3 3Diagnostic Imaging, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland.
  • | 4 4Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, 3508 TD Utrecht, Netherlands.

Abstract

OBJECTIVE

To evaluate agreement in results obtained with an MRI-based grading scheme and a macroscopic observation-based grading scheme when used to assess intervertebral disk (IVD) degeneration in cats.

SAMPLE

241 MRI and 143 macroscopic images of singular IVDs in 44 client-owned cats (40 cadaveric and 4 live).

PROCEDURES

Singular images of IVDs were obtained of live cats admitted for treatment of suspected neurologic disease (MRI images of IVDs) and of cadavers of cats euthanized for reasons unrelated to spinal disease (MRI and macroscopic images of IVDs) at the Small Animal Hospital, Vetsuisse Faculty, Zurich, Switzerland, between January 12, 2015, and October 19, 2015. The IVD images were randomized and evaluated twice by 4 observers for each grading scheme. Inter- and intraobserver reliability for the grading schemes was assessed with Cohen weighted κ analysis. Agreement and correlation between results obtained with the 2 grading schemes were determined with Cohen weighted κ and Spearman correlation coefficient (ρ) analyses, respectively.

RESULTS

Inter- and intraobserver agreement between results was substantial to almost perfect (mean weighted κ, 0.66 to 0.83 and 0.71 to 0.86, respectively) for the MRI-based grading scheme and moderate to substantial (mean weighted κ, 0.42 to 0.80 and 0.65 to 0.79, respectively) for the macroscopic observation-based grading scheme. Between the 2 grading schemes, agreement in results was moderate (mean ± SE weighted κ, 0.56 ± 0.05), and the correlation was strong (ρ = 0.73).

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that the MRI-based and macroscopic observation-based grading schemes used in the present study could be used reliably for classifying IVD degeneration in cats.

Supplementary Materials

    • Supplementary Table 1 (PDF 110 kb)
    • Supplementary Table 2 (PDF 96 kb)

Contributor Notes

Dr. Bitterli's present address is the University of Giessen, 35390 Giessen, Germany.

Address correspondence to Dr. Alisauskaite (nalisauskaite@vetclinics.uzh.ch).