The CT is performed with the patient on his or her back.

In some cases, an iodine-based contrast dye may be injected into a vein to help visualize tissues. In other cases, a CT of the lumbosacral spine may be performed after injecting contrast dye into the spinal canal during a lumbar puncture to further evaluate for nerve root compression.

The scan will last less than a few minutes.

The patient should remove all jewelry or other metals that may cause artifact in the images.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

• infant test or procedure preparation (birth to 1 year)
• toddler test or procedure preparation (1 to 3 years)
• preschooler test or procedure preparation (3 to 6 years)
• schoolage test or procedure preparation (6 to 12 years)
• adolescent test or procedure preparation (12 to 18 years)

The X-rays are painless. The primary discomfort may be from the need to lie still on the table.

A CT scan is an excellent tool for evaluating fractures and degenerative changes of the spine (such as from arthritis). MRI is a superior exam for imaging the spinal cord and intervertebral discs.

• cyst
• tumor
• "pinched nerve"
• disc herniation
• vertebral fracture
• osteoarthritis
• neoplastic disease (new abnormal tissue formation)
• infection
• metabolic disease

• osteomalacia

• Iodine is the usual contrast dye. Some patients are allergic to iodine and may have a reaction, including hives, itching, nausea, breathing difficulty, or other symptoms.
• As with any X-ray examination, radiation is potentially harmful. Consult your health care provider about the risks if multiple CT scans are needed over a period of time.
• Pregnant or breast-feeding women should consult their health care provider about the risk to the fetus.