Observer Agreement of Spine Stenosis on Magnetic Resonance Imaging Analysis of Patients With Cervical Spine Myelopathy

ObjectivesThe purpose of this study was to measure the intraobserver and interobserver reliability of magnetic resonance detection of cervical spondylotic myelopathy with and without operational guidelines.MethodsSeven radiologists examined images from 10 patients with cord signal abnormalities and clinical signs of myelopathy. Radiologist examined films twice, with and without operational guidelines designed to define stenotic changes, while blinded to the clinical findings of the patients. Analyses included a Fleiss κ assessment of intraobserver and interobserver reliability.ResultsResults demonstrated high percentage of agreement and strong intraobserver reliability and variable Fleiss κ values for interobserver assessment. Operational guidelines did not improve the intraobserver or interobserver agreement.ConclusionAlthough the percentage of agreement was high in some cases, the κ agreement was low—most likely a result of the base rate problem of a κ analysis. Sample bias toward severe degenerative changes resulted in highly prevalent selections and κ adjusted values. Nonetheless, the results do suggest that substantial intraobserver κ agreement and a wide range of interobserver κ agreement exists among trained radiologists during detection of stenotic changes associated with cervical spondylotic myelopathy.