CT scanning is an imaging method commonly used in neurosurgery and neurology to obtain high resolution images of both the bone structure and soft tissue of the head, neck, and spine. When preparing for a CT scan, a patient will be asked to remove all jewelry and dress in a hospital gown. Depending on what part of the body is being examined, a contrast agent may be given. A “contrast agent” is simply a non-painful medication, either taken by mouth or given with an IV, which will collect in areas of interest and allow them to be imaged more clearly. The contrast agent is harmless to the individual and will be quickly excreted after the procedure. Once this agent is given the patient will be asked to lie down as they are passed through a large circular scanner that emits low dose X-rays.
How Does It Work?
The X-rays will pass through the body and detectors, also located on the circular scanner, collect the X-rays as the patient moves through the circular opening. This information is then given to a computer and processed into a series of 2-dimensional cross-sectional images (images that go from the front to back of the head). In the images produced, bone will appear a bright white color and the brain itself will appear a gray color. The CT scanner will take a number of images that start from the top of the head and work down as the patient is passed through the scanner.
Will It Hurt?
The actual imaging procedure is painless but may take several minutes to complete. The typical scanning procedure is completed in five to ten minutes, depending on the amount of the body to be imaged. During this time the patient will be asked to remain still, as movement during the process will cause the resultant image to be distorted, an event known as “motion artifact.” This requirement may be difficult to achieve and cause some discomfort. Patients that are claustrophobic and small children may require mild sedation to allow for adequate image clarity.
Why Should I Get One?
Your doctor may refer you for a CT scan for the following reasons. Please note, this list is focused upon neurosurgical causes, and is not a complete list of uses for CT scanners. Also, for more information please follow the links for information on the conditions listed.
Head trauma and spine trauma
Tim Horrell, Justin F. Fraser, MD