Computed Tomography (CT Scan) Definition

Computed tomography, commonly called a CT scan, creates multiple cross-section x-ray images to view structures inside the body, especially the bones. When used to view the spine, a CT scan is typically accompanied by a myelogram to better view the nerve roots, spinal cord, discs, and other soft tissues in addition to the bones.

How a CT Scan Works

A CT scan uses a rotating x-ray scanner that moves around the body area it is imaging. Once a narrow slice of the body has been scanned, an adjacent slice is scanned and so on. The data points from these x-ray scans are then analyzed and formatted into cross-section x-ray images of the body region being studied. The computer may also stack these cross-section images, or slices, for a 3D view of bones or other structures inside the body.

When a CT Scan Is Considered

A CT scan is commonly used for a detailed image of the bones. A CT scan with myelography can also show the nerves and other soft tissues, such as discs, but an MRI is typically used instead. In cases when an MRI is not an option, such as in people who have a pacemaker, a CT scan with myelography is an alternative for viewing the soft tissues. While a CT scan is relatively safe, it is not recommended for women who are pregnant due to the radiation risks.