Imaging of degenerative disease of the cervical spine

The introduction of new techniques to the magnetic resonance imaging (MRI) armamentarium is beginning to provide an MRI examination that overcomes many of the disadvantages noted in earlier reports. An analysis of the various advantages and disadvantages of MRI, plain film myelography, and computed tomographic myelography points to a potential revision of the sequence of diagnostic studies and the workup of cervical degenerative disease. MRI might now be the appropriate first test for the evaluation of the cervical spine in a patient with symptoms referable to degenerative disease when therapeutic intervention is considered. An initial T1-weighted sagittal image with a 3-mm slice thickness will provide excellent contrast evaluation of the vertebral body marrow, disc space height, neural canal, and spinal cord. Disc herniation, canal stenosis, subluxation, and malalignment can be appreciated. Next, a fast, variable flip angle, gradient-echo sequence can be performed to increase the signal density of the cerebrospinal fluid relative to the extradural elements and cord. This provides an increased conspicuousness of extradural disease. Axial gradient-echo fast sequences, with low flip angles, will provide a second orthogonal plane with increased conspicuousness of extradural changes relative to the neural foramen and thecal sac. If necessary, additional oblique views through the neural foramen can be obtained. Finally, if intramedullary disease is considered in the differential, a gated, refocused, T2-weighted examination in the sagittal plane will provide the necessary soft-tissue contrast to detect pathology without unwanted artifact. Thus, unlike plain film or computed tomographic myelography, an examination of the entire cervical region including the osseous structures, extradural cerebrospinal fluid interface, and the spinal cord can be obtained with a single modality in an outpatient setting and in a noninvasive fashion. MRI can certainly replace plain film myelography for the overwhelming majority of situations. If surface-coil MRI fails to demonstrate an abnormality responsible for the patient's clinical symptoms, then a high-resolution computed tomographic scan with or without intrathecal contrast can be obtained. While the cost at first may seem prohibitive, the additional information that MRI is capable of providing in a noninvasive outpatient setting more than compensates for the expense.