Interobserver agreement regarding characteristics of the impaired disc level.

The number between brackets on the first row is the number of patients of which the observers suggested the same disc level as the symptomatic disc level. A en B represent the two neuroradiologists, while C represents the neurosurgeon. ‡Categories were: bulging disc versus disc herniation. ∫Categories were: yes versus no. ∥Categories were: 1) Hypointensity 2) Normal 3) Hyperintensity. ∥Categories were: 1) No vertebral endplate signal changes (VESC) 2) VESC type I 3) VESC type II. 4) VESC type III 5) Mixed VESC type I/II 6) Mixed VESC type II/III. ΨCategories were: 1) Yes, completely disappeared 2) Yes, partly disappeared 3) No disappearance. §Categories were: 1) Sub-articular zone 2) Foraminal zone 3) Extra-foraminal zone. |--Categories were: 1) Normal 2) Thickened 3) Narrowed. *Prevalence of findings too low (<10% of the reports) to calculate kappa values. **Prevalence of spinal canal stenosis too low (<10% of the reports) to calculate kappa values. ***Prevalence of thickened nerve roots too low (<10% of the reports) to calculate kappa values.