Qualitative Assessment of Cervical Spinal Stenosis: Observer Variability on CT and MR Images

BACKGROUND AND PURPOSE: Several studies have been undertaken to validate quantitative methods of evaluating cervical spinal stenosis. This study was performed to assess the degree of interobserver and intraobserver agreement in the qualitative evaluation of cervical spinal stenosis on CT myelograms and MR images. METHODS: Cervical MR images and CT myelograms of 38 patients were evaluated retrospectively. Six neuroradiologists with various backgrounds and training independently assessed the level, degree, and cause of stenosis on either MR images or CT myelograms. Unknown to the evaluators, 16 of the patients were evaluated twice to determine intraobserver variability. RESULTS: Interobserver agreement among the radiologists with regard to level, degree, and cause of stenosis on CT myelograms showed κ values of 0.50, 0.26, and 0.32, respectively, and on MR images showed κ values of 0.60, 0.31, and 0.22, respectively. Intraobserver agreement with regard to level, degree, and cause of stenosis on CT myelograms showed mean κ values of 0.69, 0.41, and 0.55, respectively, and on MR images showed mean κ values of 0.80, 0.37, and 0.40, respectively. CONCLUSION: MR imaging and CT myelographic evaluation of cervical spinal stenosis by using current qualitative methods results in significant variation in image interpretation.