Thoracic spine CT scan
CAT scan - thoracic spine; Computed axial tomography scan - thoracic spine; Computed tomography scan - thoracic spine; CT scan - upper back
A computed tomography (CT) scan of the thoracic spine is an imaging method. This uses x-rays to rapidly create detailed pictures of the middle back (thoracic spine).
How the Test is Performed
You will lie on a narrow table that slides into the center of the CT scanner.
Once you are inside the scanner, the machine's x-ray beam rotates around you. (Modern "spiral" scanners can perform the exam without stopping.)
A computer creates separate images of the body area. These are called slices. These images can be stored, viewed on a monitor, or printed on film. The slices together can create three-dimensional models of the body area.
You must be still during the exam. Movement will create blurred images. You may be told to hold your breath for short periods of time.
The scan should take only 10 to 15 minutes.
How to Prepare for the Test
Certain exams require a special dye, called contrast. Contrast is delivered into the body before the test starts. This helps certain areas show up better on the x-rays.
Contrast can be given in several ways. It may be given as an injection through:
- A vein (IV) in your hand or forearm.
- Your back into the space surrounding the spinal cord.
If contrast is used, you may also be asked not to eat or drink anything for 4 to 6 hours before the test.
Before receiving the contrast, tell your health care provider if:
- You have ever had a reaction to contrast. You may need to take medicines before the test to safely receive the dye.
- You take the diabetes medicine metformin (Glucophage). You may need to take extra steps if you take this medicine.
Find out if the CT machine has a weight limit if you weigh more than 300 pounds (135 kilograms). Too much weight can cause damage to the scanner.
You will be asked to remove jewelry and wear a hospital gown during the study.
How the Test will Feel
Some people may find it uncomfortable to lie on the hard table.
Contrast given through an IV may cause:
- Slight burning feeling
- Metallic taste in the mouth
- Warm flushing of the body
These feelings are normal and will often go away within a few seconds.
Why the Test is Performed
CT rapidly creates detailed pictures of the thoracic spine. The test may help diagnose or detect:
- Birth defects of the spine in children
- Bone fracture in the spine
- Arthritis of the spine
- Curvature of the spine
- Tumor of the spine
- Other spinal injury
Thoracic CT scan can also be used during or after:
- Myelography: An x-ray of the spinal cord and spinal nerve roots
- Discography: An x-ray of the disk
Normal Results
Results are normal if the thoracic spine looks normal.
What Abnormal Results Mean
Abnormal results may be due to:
- Birth defects of the spine
- Bone problems
- Fracture
-
Herniated (slipped) disk
Herniated (slipped) disk
A herniated (slipped) disk occurs when all or part of a disk is forced through a weakened part of the disk. This may place pressure on nearby nerves...
- Infection of the spine
-
Narrowing of the spine (
spinal stenosis
)
Spinal stenosis
Spinal stenosis is narrowing of the spinal column that causes pressure on the spinal cord, or narrowing of the openings (called neural foramina) wher...
-
Scoliosis
Scoliosis
Scoliosis is an abnormal curving of the spine. Your spine is your backbone. It runs straight down your back. Everyone's spine naturally curves a b...
- Tumor
Risks
Risks of CT scans include:
- Exposure to radiation
- Allergic reaction to contrast dye
CT scans expose you to more radiation than regular x-rays. Having many x-rays or CT scans over time may increase your risk for cancer. However, the risk from any 1 scan is small. You and your provider should weigh this risk against the benefits of getting a correct diagnosis for a medical problem.
Some people have allergies to contrast dye.
The most common type of contrast given into a vein contains iodine. People with an iodine allergy may have:
-
Nausea or vomiting
Nausea or vomiting
Nausea is feeling an urge to vomit. It is often called "being sick to your stomach. "Vomiting or throwing-up is forcing the contents of the stomach ...
-
Sneezing
Sneezing
A sneeze is a sudden, forceful, uncontrolled burst of air through the nose and mouth.
-
Itching
or
hives
Itching
Itching is a tingling or irritation of the skin that makes you want to scratch the area. Itching may occur all over the body or only in one location...
Hives
Hives are raised, often itchy, red bumps (welts) on the surface of the skin. They are usually an allergic reaction to food or medicine. They can al...
In case you are allergic, your provider may give you antihistamines (such as Benadryl) or steroids before the test.
The kidneys help remove iodine out of the body. People with kidney disease or diabetes may need to receive extra fluids after the test. This will help flush the iodine out of the body.
Rarely, the dye may cause anaphylaxis . Notify the scanner operator right away if you have any trouble breathing or swallowing. Scanners come with an intercom and speakers, so the operator can hear you at all times.
Anaphylaxis
Anaphylaxis is a life-threatening type of allergic reaction.
Considerations
The thoracic CT scan is good for evaluating large herniated disks. It can miss the smaller ones. This test with a myelogram will show a better image of the nerve roots and find smaller injuries.
References
RJ Gardocki, FX Camillo. Other disorders of the spine. In: Canale ST, Beaty JH, eds. Campbell's Operative Orthopaedics . 12th ed. Philadelphia, PA: Elsevier Mosby; 2013:chap 44.
US Food and Drug Administration. Computed tomography (CT). Updated August 7, 2014. www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/MedicalX-Rays/ucm115317.htm#4 . Accessed April 25, 2016.
Review Date: 3/10/2016
Reviewed By: C. Benjamin Ma, MD, Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery, San Francisco, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.