Kinematic magnetic resonance imaging of the upper cervical spine using a novel positioning device

Study Design. The development of a novel positioning device for magnetic resonance imaging of the upper cervical spine and an evaluation of motion patterns of the craniovertebral junction in asymptomatic volunteers as a part of the whole cervical spine motion. Objectives. To design and construct a positioning device that enables magnetic resonance imaging of the cervical spine in rotation, lateral bending, flexion, and extension in a horizontally open magnetic resonance scanner, and to define reference values for movements of the occiput (C0), the atlas (C1), and the axis (C2) in asymptomatic volunteers. Summary of Background Data. In previously used devices, the direction of motion is limited usually to flexion-extension, or the position of the head and neck are adjusted without a positioning device using semihard wedges or pillows. Methods. Magnetic resonance imaging of the upper cervical spine in 20 asymptomatic individuals (10 men and 10 women) was performed in a horizontally open 0.23-T magnetic resonance imager in progressive steps during rotation, lateral bending, and flexion-extension using axial, coronal, and sagittal imaging planes, respectively. The positions of C0, C1, and C2 were measured, and pattern of motions between segments analyzed. Lateral displacement of the atlas during lateral bending and cranial migration distance during flexion-extension were assessed. Results. The nonferromagnetic positioning device was designed and constructed. The motion patterns of the craniovertebral junction during rotation did not differ between the men and women, but in lateral bending there was a small difference between genders at C1-C2. In men, the position of C1 during flexion-extension was consistently more extended in relation to C0 and C2 than in women. Conclusions. The new positioning device allows magnetic resonance imaging of the upper cervical spine during flexion, extension, rotation, and lateral bending. To assess the relationship between C0-C1 and C1-C2 in flexion and extension, separate reference values for men and women are recommended.