Computed Tomography, or CT scan, combines x-rays with computer technology to create images of different bone and organ sections. Unlike standard x-rays which take a picture of the whole structure being examined, CT has the ability to image that same structure one “slice” at a time.
In standard x-rays, dense tissues like bones can block the view of the body parts behind them. In CT, the various slices clearly show both bone and underlying soft tissue. CT assists physicians in both diagnosis and detection of a variety of conditions at an early stage.
CT scanning can be used to obtain information about almost any body part. The amount of radiation used in CT exams is equivalent to that of standard x-ray procedures.
CT scanning is a non-invasive method of diagnosis for symptomatic patients with issues that require a view inside the body. It is a short, painless procedure and emits very low amounts of radiation.
When would I get a CT of the Head?
A physician or other medical provider may recommend a head CT to detect:
- bleeding, brain injury and skull fractures in patients with head injuries
- bleeding caused by a ruptured or leaking aneurysm in a patient with a sudden severe headache
- a blood clot or bleeding within the brain shortly after a patient exhibits symptoms of a stroke
- a stroke
- a brain tumor
- enlarged brain cavities, known as ventricles, in patients with hydrocephalus
- diseases or malformations of the skull.
Typically, CT is the first diagnostic imaging test performed in evaluating such symptoms. CT can be used to diagnose infarcts, which is the death of tissue, and other head-related abnormalities.
What Will I Experience?
A dye that contains iodine (contrast material) is often injected into the blood (intravenously) during a CT scan.
The dye makes blood vessels and certain structures or organs inside the body more visible on the CT images. If an abdominal CT scan is performed, a contrast material is usually given by mouth (orally).
During a CT scan, the area being studied is positioned inside a ring or “gantry” that is part of the CT scanner. The ring can tilt and the x-ray scanning devices within it can rotate to obtain the views needed.
According to most people, the challenging part of a CT exam is from time to time the need to lie perfectly still for a longer period. However, the technologist will keep you informed as to when to be still and when you can relax and move around.
Also, contrast material may be determined to be appropriate in order to provide better results for the radiologist to review. When administered, the contrast may cause minor discomfort.
The time required will depend upon the type of scan. If oral contrast is required, about 45 to 60 minutes is needed for the contrast to move through your digestive tract. Actual scan times vary from a few seconds to several minutes.
If no oral contrast is required, the examination will take about 15 to 30 minutes, including the time for exam preparation and interview. In some cases, additional scanning is required as scans are tailored to suit individual diagnostic needs.