Spinal CT

Alternative names
Lumbosacral spine CT; CT - lumbosacral spine

A lumbosacral spine CT involves computed topography (CT) of the lower spine and surrounding tissues.

How the test is performed

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.

How to prepare for the test

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:

How the test will feel

The X-rays are painless. The primary discomfort may be from the need to lie still on the table.
If intravenous contrast dye is given, the patient may initially feel a slight burning sensation within the injected arm, a metallic taste in the mouth, and a warm flushing of the body. These sensations are normal and usually reside within a few seconds.

Why the test is performed

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.

What abnormal results mean
Conditions that may be revealed include:

  • cyst  
  • tumor  
  • “pinched nerve”  
  • disc herniation  
  • vertebral fracture  
  • Osteoarthritis  
  • neoplastic disease (new abnormal tissue formation)  
  • infection  
  • metabolic disease

Additional conditions under which the test may be performed:

  • osteomalacia

What the risks are

  • 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.


Johns Hopkins patient information

Last revised: December 3, 2012
by Gevorg A. Poghosian, Ph.D.

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