Comparison of computed tomography myelography and magnetic resonance imaging in the evaluation of cervical spondylotic myelopathy and radiculopathy

Study Design. A cross-sectional retrospective radiologic study. Objectives. To establish concordance rates between interpretations of compu ted tomography myelography and magnetic resonance imaging in patients with degenerative cervical spine disease. Summary of Background Data. Observed discrepancies in interpretation of com puted tomography myelography and magnetic resonance imaging question the re liability of comparisons between these two methods. Methods. This study blindly and randomly evaluated cervical computed tomogr aphy myelography and magnetic resonance imaging in 20 patients referred for clinically diagnosed cervical spondylotic radiculopathy, myelopathy, or bo th. The discovertebral joints, facet joints, lateral recesses, cord size, s pinal canal, and neural foramina also were evaluated with graded scales. Al l results were subjected to the kappa statistic for strength of agreement. Results. Agreement for interpretation of the discovertebral junction occurr ed in 144 of 240 sites (60%), indicating only moderately good intermethod c oncordance (kappa = 0.44). Intermethod agreement on the characterization of facet joint disease was only moderately good (143 of 160 sites; 89.4%; kap pa = 0.52), and on characterization of lateral recess disease was poor (125 of 160 sites; 78.1%; kappa = 0.20). On degree of spinal canal compromise, there was agreement within one grade in 199 of 240 sites (82.9%; kappa = 0. 42). Intermethod agreement on neural foraminal encroachment and cord size w as only moderately good (kappa = 0.42 and 0.46, respectively). Computed tom ography myelography tended to upgrade the spinal canal narrowing and neural foraminal encroachment. Conclusions. For most parameters of interpretation, the degree of concordan ce between computed tomography myelography and magnetic resonance imaging i s only moderately good, with discrepancies noted especially in the differen tiation of disc and bony pathology. These methods should be viewed as compl ementary studies.