Spinal Cord CT Scan: What to Expect and What It Detects

A computed tomography (CT) scan uses X-rays and computer technology to create detailed cross-sectional images of the body. A spinal CT focuses on the spine’s structures, including the vertebrae, intervertebral discs, and the spinal canal. This procedure provides significantly more detail of the bony structures than a standard X-ray. While magnetic resonance imaging (MRI) is better for visualizing soft tissues like the spinal cord, a CT scan excels at showing bone with high clarity. The images generated can be viewed in multiple planes or even as three-dimensional models, giving doctors a comprehensive view of the spine’s anatomy and any potential issues.

Why Spinal Cord CT Scans Are Ordered

A physician may order a spinal CT scan for several reasons. It is a common diagnostic step for patients who have experienced acute trauma, such as from a car accident or a fall, to quickly identify fractures or dislocations. The speed of a CT scan makes it useful in emergency situations where a rapid diagnosis is needed.

These scans are also used to investigate the source of persistent back and neck pain. Symptoms like weakness, numbness, or tingling that radiates into the arms or legs can indicate a problem like a herniated disc or spinal stenosis. A spinal CT is also a tool for pre-operative planning and to assess degenerative conditions like osteoarthritis or congenital issues.

The Spinal Cord CT Scan Experience

Before the scan, you may be asked to refrain from eating or drinking for a few hours, especially if a contrast material will be used. You must inform the medical staff about any recent illnesses, allergies, medications you are taking, and any possibility of pregnancy. You will also need to remove metal objects like jewelry and hearing aids, as they can interfere with the images, and you will likely change into a hospital gown.

For some spinal CT scans, an intravenous (IV) contrast dye is administered to make certain structures like blood vessels show up more clearly. A technologist will insert an IV into a vein in your arm or hand. When the dye is injected, it is common to experience a temporary feeling of warmth spreading through your body or a metallic taste in your mouth, which passes within a few minutes.

During the procedure, you will lie on a narrow table that slides into the center of the large, doughnut-shaped CT scanner. The scanner will rotate around you, and you might hear buzzing or clicking noises. A technologist will be in an adjacent room but can see, hear, and speak with you at all times. It is important to remain as still as possible during the scan, which takes about 10 to 30 minutes, as movement can blur the images.

After the scan, the IV will be removed if one was used, and you can return to your normal activities. If you received contrast dye, you might be observed for a short period to ensure there are no adverse reactions. Drinking plenty of fluids after a scan with contrast is recommended to help flush the dye from your system.

What Spinal Cord CT Scans Can Detect

A spinal CT scan is highly effective at identifying a wide range of conditions, primarily because of its ability to produce detailed images of bone. It can clearly visualize issues that might be missed on a standard X-ray. Common findings include:

• Fractures and Misalignment: This includes subtle vertebral compression fractures from osteoporosis, severe burst fractures from trauma, and dislocations. The scan can also precisely assess congenital abnormalities like scoliosis or spina bifida occulta.
• Degenerative Conditions: A CT scan reveals the extent of spinal stenosis, where bony overgrowths (bone spurs) narrow the spinal canal. It also provides a clear view of facet joint arthritis, which affects the small joints between vertebrae.
• Disc Herniations: While MRI is the primary tool for looking at intervertebral discs, a CT can detect disc herniations, especially if they are hardened by calcium deposits.
• Infections and Tumors: It can identify changes in bone structure caused by infections like osteomyelitis or discitis, and find tumors that originate in the vertebrae or have spread there from other parts of the body.
• Post-Operative Assessment: Surgeons use CT scans to check the placement and integrity of surgical hardware, such as screws and rods, and to evaluate the progress of spinal fusion procedures.

Key Considerations for Spinal CT Imaging

A primary consideration with any CT scan is the use of ionizing radiation. The radiation dose is higher than a standard X-ray, but the benefit of an accurate diagnosis is considered to outweigh the potential risk. Medical facilities follow the ALARA principle (“As Low As Reasonably Achievable”) to minimize exposure by using the lowest dose necessary for quality images, with special adjustments for children who are more sensitive to radiation. A spinal CT scan delivers a radiation dose equivalent to about two years of natural background radiation.

If contrast dye is required, there is a small risk of an allergic reaction to the iodine-based material, which can range from mild itching to more severe responses. It is important to inform your doctor of any known allergies or previous reactions to contrast agents. The dye is filtered out by the kidneys, so your doctor will need to know about any pre-existing kidney problems.

A CT scan is often preferred over an MRI in specific situations. Its speed is a major advantage in emergency and trauma settings. For imaging fine bony detail, such as in the detection of fractures or bone spurs, CT is superior to MRI. A CT scan is also a suitable alternative for patients who cannot undergo an MRI due to having certain implanted medical devices like pacemakers or cochlear implants.