The assessment of cervical spine kinematics: A comparison of iMR and conventional radiographic techniques

Objective: To develop and appraise a non-invasive method of determining disruptions to cervical segment mechanics.

Design: A modified open magnetic resonance imaging system and post-process analysis tool were used to determine relative cervical vertebrae rotations and translations in a cohort of symptomatic patients, the results of which were compared to validated precision measures obtained from lateral radiographs. Methods: The cervical motion of 14 subjects with chronic neck symptoms were investigated in neutral, full flexion and full extension positions under voluntary neuromuscular control using open magnetic resonance imaging and lateral röntgenograms. Planar rotations and translations were calculated from the MRI images using the method of Dupuis et al. [8], and compared for agreement with the precision sagittal plane measurement technique of Frobin and colleagues [12, taken from the subjects lateral röntgenograms.

Results: The interventional Magnetic Resonance method produced rotational results of up to 10° above and 9°c (SE 1.22) below the method of Frobin et al. [12], and translational results of 18 mm above or below (SE 2.12). The error of repeatability in the interventional Magnetic Resonance method was not significant (rotation P = 0.68, Translation P = 0.96).

Conclusions: The disparity between methods limits the potential of Magnetic Resonance Imaging in clinical trials particularly those investigations into pseudarthrosis and instability.