The computerized axial tomography scan-known as a CT or CAT scan-is a simple, non-invasive procedure that enables medical professionals to quickly and safely obtain sophisticated and accurate diagnostic information on your brain, chest, abdomen, pelvis, spine and extremities.
If your physician has recommended a CT scan, you can rest assured that preparation for the exam is simple and the procedure itself is painless and safe.
What You Can Expect
The first thing you will notice when you enter the CT scan examination room is the CT scan machine itself-a table surrounded by a large donut-shaped cylinder. During the exam, you simply lie still on the table as a technologist slowly advances the table into the proper position. The cylinder will rotate slowly around the table, as thin x-ray beams take cross-sectional "snapshots" of the area of your body being examined. These snapshots are then reconstructed by the system's computer to create comprehensive, three-dimensional pictures within seconds.
The cylinder may also be tilted to collect images from various angles, but this will not touch you or disrupt the table you are lying on. These angled images allow your doctor and the radiologist to see many different cross-sections of the part of your body being scanned-something not possible with traditional x-rays.
Don't be concerned if you hear clicking sounds as the cylinder rotates and the pictures are taken—that's simply the x-ray camera and the cylinder gears at work.
The entire procedure is fast, pain free, and produces important medical information.
Before the Exam
If you are having a body CT scan, you may be asked to drink only clear liquids and abstain from solid foods before the exam.
If you are or could be pregnant or if you have asthma, you should tell your physician before having any type of CT scan. You should also let your physician know if you have ever had a reaction to a contrast agent or if you have any allergies to food, especially shellfish, or medication.
At the Exam
You may be asked to remove your watch, jewelry and other metallic objects (such as hairpins or barrettes) before lying on the table. Patients having body CT scans will need to undress and wear a hospital gown. If you are having a contrast-enhanced CT scan (CECT), a contrast agent or "dye" is used to help provide clearer pictures. This dye will be injected into a vein, generally in your arm.
Certain examinations may require more or different instructions as recommended by your physician and/or radiologist. This is meant to be a general guideline only and each patient should always follow the directions of his/her personal physician or radiologist.
After the Exam
You can return to your regular eating habits and activities after your exam. If you were given a contrast agent, it will be naturally eliminated from your body within a few hours of the exam.
Obtaining Your Results
A radiologist will read your scans and provide your physician with a full report. Your physician will contact you with the results within a few days.
Some additional Answers
How does a CT scan differ from a traditional x-ray?
CT scans can be up to 100 times more sensitive than conventional x-rays so radiologists can distinguish subtle differences in soft tissues that may not be detected with regular x-rays. CT scans also use computer technology to create much clearer images so doctors can gather more detailed information to help their patients.
Should I be concerned about the radiation associated with the x-rays being taken during the CT scan?
Not at all. CT scans require very low doses of radiation that are well within safe limits. You should also keep in mind that the value of the information gathered during a CT scan far outweighs any risk.
Who performs the exam?
The procedure is done by a technologist and/or a radiologist both specially trained to conduct these types of tests.
Is the contrast agent or "dye" painful?
No, though some people feel a warm sensation as it enters the body. If you do feel any discomfort during the exam or have had a reaction to a contrast agent before, you should inform the technologist or your physician.
What if I'm too nervous to lie still on the table?
Mild sedatives may be prescribed to help you relax before the exam.
Be sure to discuss how you feel and any questions you may have with your doctor or the radiologist before your exam. These professionals will do everything in their power to make you feel comfortable before and during your CT scan.
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INDICATIONS and IMPORTANT SAFETY INFORMATION
MAGNEVIST® (gadopentetate dimeglumine) Injection
INDICATIONS AND USAGE
Central Nervous System: MAGNEVIST® (gadopentetate dimeglumine) Injection is indicated for use with magnetic resonance imaging (MRI) in adults, and pediatric patients (2 years of age and older) to visualize lesions with abnormal vascularity in the brain (intracranial lesions), spine and associated tissues. MAGNEVIST Injection has been shown to facilitate visualization of intracranial lesions including but not limited to tumors.
Extracranial/Extraspinal Tissues: MAGNEVIST is indicated for use with MRI in adults and pediatric patients (2 years of age and older) to facilitate the visualization of lesions with abnormal vascularity in the head and neck.
Body: MAGNEVIST Injection is indicated for use in MRI in adults and pediatric patients (2 years of age and older) to facilitate the visualization of lesions with abnormal vascularity in the body (excluding the heart).
IMPORTANT SAFETY INFORMATION
WARNING: NEPHROGENIC SYSTEMIC FIBROSIS
Gadolinium-based contrast agents increase the risk for nephrogenic systemic fibrosis (NSF) in patients with:
acute or chronic severe renal insufficiency (glomerular filtration rate < 30 mL/min/1.73m2), or
acute renal insufficiency of any severity due to the hepato-renal syndrome or in the perioperative liver transplantation period.
In these patients, avoid use of gadolinium-based contrast agents unless the diagnostic information is essential and not available with non-contrast enhanced magnetic resonance imaging (MRI). NSF may result in fatal or debilitating systemic fibrosis affecting the skin, muscle and internal organs. Screen all patients for renal dysfunction by obtaining a history and/or laboratory tests. When administering a gadolinium-based contrast agent, do not exceed the recommended dose and allow a sufficient period of time for elimination of the agent from the body prior to any readministration.
The possibility of serious or life-threatening anaphylactic or anaphylactoid reactions, including cardiovascular, respiratory, and/or cutaneous manifestations, should always be considered. As with other paramagnetic contrast agents, caution should be exercised in patients with renal insufficiency due to the possibility of further deterioration in renal function. As with other injectable products, cases of phlebitis and thrombophlebitis have been reported; assessment of the dosed limb for the development of injection site reactions is recommended.
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.
EOVIST® (gadoxetate disodium) Injection is a gadolinium-based contrast agent indicated for intravenous use in T1-weighted magnetic resonance imaging (MRI) of the liver to detect and characterize lesions in adults with known or suspected focal liver disease.
IMPORTANT SAFETY INFORMATION
WARNING: NEPHROGENIC SYSTEMIC FIBROSIS
Gadolinium-based contrast agents increase the risk for nephrogenic systemic fibrosis (NSF) in patients with:
acute or chronic severe renal insufficiency (glomerular filtration rate < 30 mL/min/1.73m2), or
acute renal insufficiency of any severity due to the hepato-renal syndrome or in the perioperative liver transplantation period.
In these patients, avoid use of gadolinium-based contrast agents unless the diagnostic information is essential and not available with non-contrast enhanced magnetic resonance imaging (MRI). NSF may result in fatal or debilitating systemic fibrosis affecting the skin, muscle and internal organs. Screen all patients for renal dysfunction by obtaining a history and/or laboratory tests. When administering a gadolinium-based contrast agent, do not exceed the recommended dose and allow a sufficient period of time for elimination of the agent from the body prior to any readministration.
The possibility of serious or life-threatening anaphylactoid/hypersensitivity reactions with cardiovascular, respiratory and/or cutaneous manifestations should always be considered. The most common adverse reactions observed in clinical trials at the recommended dose included feeling hot, nausea and headache.
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.
ULTRAVIST® (iopromide) Injection is an iodinated contrast agent indicated for:
Intra-arterial Procedures*: 150 mgI/mL for intra-arterial digital subtraction angiography (IA-DSA); 300 mgI/mL for cerebral arteriography and peripheral arteriography; 370 mgI/mL for coronary arteriography and left ventriculography, visceral angiography, and aortography.
Intravenous Procedures*: 240 mgI/mL for peripheral venography; 300 mgI/mL for excretory urography; 300 mgI/mL and 370 mgI/mL for contrast Computed Tomography (CT) of the head and body (intrathoracic, intra-abdominal and retroperitoneal regions) for the evaluation of neoplastic and non-neoplastic lesions. The usefulness of contrast enhancement for the investigation of the retrobulbar space and of low grade or infiltrative glioma has not been demonstrated.
*For information on the concentrations and doses for the Pediatric Population [see Dosage and Administration (2.3) and Use in Specific Populations (8.4) in the full prescribing information].
IMPORTANT SAFETY INFORMATION
WARNING: NOT FOR INTRATHECAL USE Inadvertent intrathecal administration may cause death, convulsions, cerebral hemorrhage, coma, paralysis, arachnoiditis, acute renal failure, cardiac arrest, seizures, rhabdomyolysis, hyperthermia, and brain edema.
CONTRAINDICATIONS ULTRAVIST Injection is contraindicated for intrathecal use.
Preparatory dehydration (e.g. prolonged fasting and the administration of a laxative before ULTRAVIST Injection) is contraindicated in pediatric patients because of risk of renal failure.
WARNINGS AND PRECAUTIONS Life-threatening or fatal anaphylactoid reactions may occur during or after Ultravist administration. Acute renal failure may occur following ULTRAVIST administration, particularly in patients with renal insufficiency, diabetes, multiple myeloma. Hemodynamic disturbances including shock and cardiac arrest may occur during or shortly after administration of ULTRAVIST. Angiography may be associated with local and distal organ damage, ischemia, thromboembolism and organ failure.
MOST COMMON ADVERSE REACTIONS Most common adverse reactions (>1%) are headache, dysguesia, abnormal vision, chest pain, vasodilatation, nausea, vomiting, back pain, urinary urgency, injection site and infusion site reactions, and pain.
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.
