Reliability of a magnetic resonance imaging-based grading system for cervical intervertebral disc degeneration

J Spinal Disord Tech. 2008 Jun;21(4):288-92. doi: 10.1097/BSD.0b013e31813c0e59.


Study design: This was a radiographic reliability study of a novel grading system for cervical intervertebral disc degeneration.

Objectives: This study aimed to develop and test the reliability of a reproducible grading system for cervical intervertebral disc degeneration on the basis of the routine magnetic resonance imaging (MRI).

Summary of background data: Cervical disc degeneration is common after middle age, and the morphology of cervical disc degenerative disease has often been studied using MRI. There are few specific MRI-based grading systems for cervical intervertebral disc degeneration despite the clinical importance of this problem. This study proposes a novel reproducible grading system for cervical disc degeneration and demonstrates the reliability of this classification scheme.

Methods: A grading system for cervical intervertebral disc degeneration was developed based on relevant previous literature. MRI grading of 300 cervical intervertebral discs using T2-weighted sagittal images was performed by 4 spinal surgeons (observers) in a blinded fashion. Intraobserver and interobserver reliabilities were assessed by calculating kappa statistics.

Results: Grade I degeneration was observed in 27 discs (9.0%); grade II, in 56 (18.7%); grade III, in 124 (41.3%); grade IV, in 67 (22.3%); and grade V, in 26 (8.7%) discs. Kappa coefficients for intraobserver and interobserver agreements ranged from substantial to excellent (intraobserver, 0.907 to 0.950 and interobserver, 0.730 to 0.826). Complete agreement was obtained, on an average, in 72.1% of the discs. A difference of 1, 2, and 3 grades was observed in 22.4%, 3.3%, and 0.2% discs, respectively.

Conclusions: This grading system is comprehensive and easily applicable with sufficient reproducibility. It can be used as a common nomenclature for research and discussions.

Publication types

  • Randomized Controlled Trial
  • Validation Study

MeSH terms

  • Adult
  • Aged
  • Cervical Vertebrae*
  • Female
  • Humans
  • Intervertebral Disc Displacement / pathology*
  • Magnetic Resonance Imaging / standards*
  • Magnetic Resonance Imaging / statistics & numerical data
  • Male
  • Middle Aged
  • Observer Variation
  • Prospective Studies
  • Reproducibility of Results
  • Severity of Illness Index*