A spinal Computed Tomography (CT) scan utilizes a rotating X-ray beam and computer processing to generate detailed cross-sectional images of the spine. This diagnostic method creates “slices” of the body’s interior, providing a far more intricate view than standard X-rays. It is particularly effective at visualizing the dense, bony structures of the vertebrae. The CT scan serves as a rapid and accurate diagnostic instrument when high-resolution detail of the bone structure and surrounding neural tissues is required.
Conditions Diagnosed
The primary strength of a spinal CT scan is its ability to identify issues related to the bony architecture of the spine. In acute situations, such as after a traumatic injury, a CT scan is performed to detect fractures, dislocations, or other damage to the vertebral column. It can pinpoint the exact location and severity of damage.
The scan evaluates bony abnormalities that can compress the spinal cord or nerves, including spinal stenosis, a narrowing of the spinal canal caused by bone spurs or enlarged facet joints. For patients who have undergone surgery, a CT scan checks the placement and integrity of spinal hardware, such as rods and screws, and evaluates postsurgical healing.
A spinal CT scan also helps identify tumors, cysts, or calcified masses. It is used to assess congenital defects, which are structural anomalies present from birth, such as spina bifida or vertebral fusion. In cases of chronic pain, the scan reveals signs of degenerative conditions like osteoarthritis, including bone spurs and joint-space narrowing.
What to Expect During the Scan
You will be asked to remove all metal objects, including jewelry and eyeglasses, as metal can interfere with image quality. If the scan requires intravenous (IV) contrast dye, you may be instructed to fast for a few hours beforehand. The contrast material is injected into a vein to help highlight blood vessels, soft tissues, and potential areas of inflammation or tumor growth.
You will lie on a narrow, motorized table that slides into the CT scanner. The technologist will position you, often using straps or pillows, to ensure you remain perfectly still. During the scan, the table moves slowly as the X-ray tube rotates around you, collecting data from multiple angles.
If contrast is administered, you may experience a temporary warm, flushing sensation or a metallic taste in your mouth; these are normal side effects that dissipate quickly. The entire scanning process often takes only 10 to 15 minutes.
CT Myelogram
If a CT myelogram is performed, a specific contrast dye is injected directly into the spinal fluid via a lumbar puncture before the CT scan to clearly outline the spinal cord and nerve roots.
Important Safety Considerations
A primary consideration for a CT scan is the patient’s exposure to ionizing radiation, which is greater than that from a standard X-ray. The effective dose for a spine CT scan is often estimated to be around 6 millisieverts (mSv), which is roughly equivalent to two years of natural background radiation. Medical professionals adhere to the principle of using the lowest radiation dose possible to obtain the necessary diagnostic information.
If contrast dye is used, there is a risk of a reaction, although most reactions are mild, such as temporary itching or a rash. The technologist will monitor you following the injection. Patients with pre-existing kidney conditions must inform their doctor, as the contrast agent is filtered through the kidneys and can potentially affect function.
Women who are pregnant or suspect they might be pregnant must inform the technologist, as the radiation exposure carries a risk to the developing fetus, and an alternative imaging method may be recommended. The benefits of the diagnostic information provided by the CT scan are carefully weighed against these small, potential risks, ensuring the procedure is justified for your specific medical situation.