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Are there risks in obtaining a CT scan?
A CT scan is a very low-risk procedure. The most common problem is an adverse reaction to intravenous contrast material. Intravenous contrast is usually an iodine-based liquid given in the vein, which makes many organs and structures, such as the kidneys and blood vessels, much more visible on the CT scan. There may be resulting itching, a rash, hives, or a feeling of warmth throughout the body. These are usually self-limiting reactions that go away rather quickly. If needed, antihistamines can be given to help relieve the symptoms. A more serious allergic reaction to intravenous contrast is called an anaphylactic reaction. When this occurs, the patient may experience severe hives and/or extreme difficulty in breathing. This reaction is quite rare, but is potentially life-threatening if not treated. Medications which may include corticosteroids, antihistamines, and epinephrine can reverse this adverse reaction.
Toxicity to the kidneys which can result in kidney failure is an extremely rare complication of the intravenous contrast material used in CT scans. People with diabetes, people who are dehydrated, or patients who already have impaired kidney function are most prone to this reaction. Newer intravenous contrast agents have been developed, such as Isovue, which have nearly eliminated this complication.
The amount of radiation a person receives during a CT scan is minimal. In men and nonpregnant women, it has not been shown to produce any adverse effects. If a woman is pregnant, there may be a potential risk to the fetus, especially in the first trimester of the pregnancy. If a woman is pregnant, she should inform her doctor of her condition and discuss other potential methods of imaging, such as an ultrasound, which are not harmful to the fetus. However, the the radiation exposure during a CT scan may cause a very small increase in a person's lifetime risk of developing cancer. This concern is often viewed as more important for children, because the cancer risk per dose of radiation is higher for younger patients than adults, and younger patients have a longer life expectancy. Still, the risks of exposure to radiation must be weighed against the benefits of using CT scanning to diagnose or treat illness. CT scanners can be modified to deliver exposures that are more appropriate for pediatric patients. Most physicians suggest that all radiation exposure to patients should be kept to a minimum; those patients that "doctor shop" or repeatedly go to emergency departments for a "CT” put themselves at risk for radiation-caused problems.