MRI to measure cervical sagittal parameters: a comparison with plain radiographs.

ABSTRACT

INTRODUCTION: The inability to visualize the sternum tip and T1 vertebra on radiographs may decrease the accuracy of the measurements of cervical sagittal parameters. The object of this study is to investigate the value of MRI to measure cervical sagittal parameters and to compare the data of cervical sagittal parameters on radiographs and MR images. MATERIALS AND METHODS: Fifty-two asymptomatic adults were recruited. Each subject had both an MRI and radiographs of the cervical spine. Data, including C2-7 lordosis (CL), T1 slope (T1S), thoracic inlet angle (TIA), neck tilt (NT), and T1S minus C2-7 lordosis (T1S-CL), on radiographs and MRI were collected and analyzed. RESULTS: There were significant differences in CL, T1S, and T1S-CL, between X-ray and MR imaging, but not in TIA and NT. Each of the radiographic cervical sagittal parameters had a significant relationship with the corresponding value on MRI, and the correlation between radiographic and MRI measurement of TIA was the most significant of all parameters. CONCLUSIONS: Positional change may significantly influence most sagittal parameters. Supine MRI cannot substitute for upright cervical radiographs to measure most cervical sagittal parameters except for TIA in an asymptomatic population.