Spinal disease is a very common cause of neck and back pain. Patients presenting with spinal pain form a very important group at the Pain Clinic. Hence, appropriate evaluation of spinal disease is essential to provide excellent care to the patients.
This chapter describes the different imaging modalities available for the evaluation of spinal disease and imaging appearance of different spinal abnormalities. Emphasis will be laid on degenerative disease and postoperative changes with a brief note on nondegenerative diseases of the spine and diseases of the spinal cord.
IMAGING MODALITIES FOR THE EVALUATION OF SPINAL DISEASE
Plain radiography (PXR) is easily available and less expensive. It can be used as a screening study in patients presenting with pain to identify gross osseous and soft-tissue abnormalities related to degenerative changes, and for evaluation of hardware. Flexion and extension views are helpful in assessing instability and intersegmental mobility. Composite views are helpful in the evaluation of scoliosis. However, plain radiographs are not ideal for detailed evaluation of the spine and spinal contents.
Computed tomography (CT) provides very good anatomic and structural details of the spine, in particular, the osseous details related to degenerative changes, trauma, and tumors. The spatial resolution is very good; however, the contrast resolution is low. Hence, it is not ideal for the evaluation of cord, nerve, and soft-tissue abnormalities, although gross abnormalities can be identified based on the alteration of the normal outlines of the structures and natural contrast among fat, bone, and disk. Usually, noncontrast studies are performed for evaluation of osseous details. Intravenous iodinated contrast medium is used for obtaining postcontrast CT images for evaluation of infection and tumors if Magnetic Resonance Imaging (MRI) cannot be performed. MRI is a better modality for these indications.
With the advent of newer generation scanners with multiple detectors, studies can be performed very rapidly and can include larger segments of the spine. Postprocessing methods help obtain very good reformations in multiple planes and form part of the standard algorithm of spinal imaging.
CT does have certain disadvantages that include risk of ionizing radiation, allergic reaction to intravenous contrast (IV) agent, and low-contrast resolution for assessment of intrathecal and soft-tissue abnormalities.
MAGNETIC RESONANCE IMAGING
Magnetic resonance imaging studies are performed using radiofrequency waves and, hence, have no risk of ionizing radiation. MRI is mostly used for detailed assessment and characterization of spinal disease, including cord and neural structures. It provides excellent anatomical details with high-contrast resolution. Acquisition of images using different sequences and in different planes helps in better characterization and localization of abnormalities compared to CT studies. Intravenous contrast agents such as gadolinium-based agents are helpful in the characterization of infective, inflammatory, vascular, and neoplastic lesions. For the evaluation of traumatic, degenerative, and ...