CT and CT Angiography
Computed Tomography (CT) is an imaging modality which has become the primary tool for diagnosis of many medical conditions. Patients lie on a table which moves through a the circular CT scanner which emits x-rays to create images of the body and its internal structures. CT scans are often able to identify abnormalities within the body only a few millimeters in size.
Sometimes this is done during or after the use of contrast, which is an iodine-based material given through an IV and helps to better show blood vessels, organs, and other internal structures. Your doctor will decide whether to use IV contrast, sometimes with the guidance of the radiologist. Occasionally, after a scan without contrast has been performed, it may be necessary to repeat the scan with contrast to better evaluate a possible abnormality. Some scans are also performed with oral contrast, which is contrast material that you drink before the scans to better show the digestive tract and associated structures.
CT scans are noninvasive or minimally invasive (requiring only an IV). Scans are very fast and painless, though some people feel a warmth inside the body during contrast administration.
CT Angiography (CTA) is a specialized form of CT with contrast in which the scan is performed during or shortly after contrast administration. CTA is utilized to specifically evaluate blood vessels, which may be in the brain, neck, chest, abdomen, or extremities. It allows radiologists to carefully evaluate the blood vessels for blockages or damage to the blood vessels such aneurysms, or dissection (abnormal tearing of the blood vessel wall). It is also used to evaluate for active bleeding which may be life threatening.
Preparing for CT
To best prepare for a CT scan, be sure to have a current list of your medications and any allergies so that we can ensure safety during contrast injection. You may be asked to remove some clothing and wear a hospital gown. You will also be asked to remove metal objects such as jewelry, dentures, eyeglasses, or belts with metal buckles, as these may cause interference with the scan. If appropriate, you may be asked to drink oral contrast before the scan. The CT technologist is responsible for ensuring your safety and that you are properly prepared for the best quality scan possible.
If you are to receive IV contrast during the CT scan, you may need blood tests to evaluate your kidney function. Patients with impaired kidney function are at higher risk of increased damage to the kidneys after receiving IV contrast. If your kidney function is below a certain level and you are not on dialysis, your scan may be changed to a non-contrast scan. The decision to give contrast should be a collaborative decision made by the patient, his or her doctor, and the radiologist, taking into account the medical necessity for contrast and the potential risks.
Is CT scanning safe?
CT scanning is overall extremely safe, effective, and efficient, which is why it has become such a commonly used tool for medical diagnosis. However, scanning does require some exposure to radiation. The radiation dose of a single scan is unlikely to be of any significance, though the effect of many scans may have long term effects that are as yet unproven. Generally, the risks of a single scan are outweighed by the benefits of those scans, though if you have had several CT scans in the past it is prudent to discuss with your doctor whether additional scanning is necessary for directing your care.
IV contrast is also generally very safe. Most patients have no effect from contrast except a temporary feeling of warmth near the injection site or in the body during the scan. In rare instances ,patients are allergic to contrast. If you have a known mild to moderate allergy such as hives or itching, you may be asked to take pre-medication to reduce the risk of an allergic reaction or to reduce the severity of any reaction. If you have a severe contrast allergy such as severe swelling of the head or neck, difficulty breathing, anaphylaxis, or the need to be hospitalized after receiving contrast, it may not be safe to receive IV contrast except in emergency situations where contrast is absolutely necessary.
IV contrast is eliminated from the body through the kidneys. Patients with impaired kidney function may be at higher risk for additional damage to the kidneys and should discuss with their doctor whether contrast is necessary. Your radiologist will provide guidance when needed. You may need recent blood work done to evaluate your kidney function before receiving IV contrast.
To learn more or for any questions, please call (714) 970-0200 or email office@fullertonradiology.org. For facility specific questions or concerns, please use the Locations page to find the appropriate contact information. Fullerton Radiology Medical Group radiologist physicians help doctors and patients at its affiliated locations, which serve the Anaheim, Brea, Corona, Fullerton, Orange, Placentia, Riverside, Yorba Linda, Monterey Park, Alhambra, San Gabriel Valley, Chino Valley, Chino Hills, San Dimas, Montclair, City of Industry, and neighboring communities.