What are contrast materials and how do they work Contrast materials also called contrast agents or contrast media are used to improve pictures of the inside of the body produced by xrays computed tomography CT magnetic resonance MR imaging and ultrasound Often contrast mater ID: 1039247
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2. Contrast Media in Medical Imaging Techniques
3. What are contrast materials and how do they work?
4. Contrast materials: also called contrast agents or contrast media, are used to improve pictures of the inside of the body produced by x-rays, computed tomography (CT), magnetic resonance (MR) imaging, and ultrasound. Often, contrast materials allow the radiologist to distinguish normal from abnormal conditions.
5. They are substances that temporarily change the way x-rays or other imaging tools interact with the body
6. MODE OF ADMINISTRATION Orally (Swallowed).2. Rectally (Enema)Intravenously V & A
7. Elimination of Contrast Agents Following an imaging exam with contrast material, the material is eliminated by one of the following way:- 1- Absorbed by the body or 2- Eliminated through urine or 3- Bowel movements (Feces).
8. Types of contrast media
9. Air and Gasses
10. POSITVE CONTRAST MEDIA1.Iodine-based C.M. A contrast materials can have a chemical structure that includes iodine, a naturally occurring chemical element. These contrast materials can be injected into veins or arteries, within the disks or the fluid spaces of the spine, and into other body cavities.
11. iodinate contrast media in CT scan
12. Dose of iodinate in the different types:-Ominpaque 350 (Iohexol) GE Healthcare Visipaque 320 (Iodixanol) GE HealthcareUltravist 370 (Iopromide) Bayer HealthcareOpitiray 320 (Ioversol) Mallinckrodt Inc
13. Cont………2-Barium-sulfate: is the most common contrast material taken by mouth, or orally. It is also used rectally and is available in several forms, including:1.Powder, which is mixed with water before administration2.Liquid3.Paste4.Tablet
14. Barium Sulfate Contrast Materials in CT-Scan
15. Physics of contrast materialsWhen iodine-based and barium-sulfate contrast materials are present in a specific area of the body, they block or limit the ability of x-rays to pass through. As a result, blood vessels, organs and other body tissue that temporarily contain iodine-based or barium compounds change their appearance on x-ray or CT images.
16. CONT……..The ability to distinguish between tissues depends upon two types of interactions between photons and matter: Compton scattering and photoelectric absorption. Both these interactions depend upon physical density, but the also depends upon atomic number of the matter. As iodine has a high atomic number, 53, compared to most tissues in the body, the administration of iodinated material produces image contrast due to differential photoelectric absorption.
17. Which imaging exams use contrast materials?
18. Oral Contrast MaterialsBarium-sulfate contrast materials that are swallowed or administered by mouth (orally) are used to enhance x-ray and CT images of the gastrointestinal (GI) tract, including:. pharynx. esophagus. stomach. the small intestine. the large intestine (colon)
19. Cont……….. Rectal Contrast MaterialsBarium-sulfate contrast materials that are administered by enema (rectally) are used to enhance x-ray and CT images of the lower gastrointestinal (GI) tract (colon and rectum).
20. Intravenous Contrast MaterialsIodine-based are injected into intravenously to used to enhance x-ray and CT images. Typically they are used to enhance the:Internal organs, including the heart, lungs, liver, adrenal glands, kidneys, pancreas, gallbladder, spleen, uterus, and bladderGastrointestinal tract, including the stomach, small intestine and large intestine .Arteries and veins of the body, including vessels in the brain, neck, chest, abdomen, pelvis and legsSoft tissues of the body, including the muscles, fat ,skin, brain and Breast.
21. How should I prepare my patient with contrast material?
22. Because contrast materials carry a slight risk of causing an allergic reaction or adverse reaction, you should tell your doctor about:1.Allergies to contrast materials, food, drugs, dyes, preservatives.2.Medications you are taking, including herbal supplements.3.Recent illnesses, surgeries, or other medical conditions.4.History of asthma and hay fever.5.History of heart disease, diabetes, kidney disease, thyroid problems or sickle cell anemia.
23. Side effects and adverse allergic reactions
24. Barium Sulfate Contrast Materialsstomach cramps ,diarrhea, nausea, vomiting and constipation.Hives, itching, red skin, swelling of the throat, difficulty breathing or swallowingYou are at greater risk of an adverse reaction to barium-sulfate contrast materials if:1. you have a history of asthma, hay fever, or other allergies, which will increase your risk of an allergic reaction to the additives in the barium-sulfate agent.2. you have cystic fibrosis, which will increase the risk of blockage in the small bowel.3. you are severely dehydrated, which may cause severe constipation.4. you have an intestinal blockage or perforation that could made worse by a barium-sulfate agent.
25. Iodine-based Contrast MaterialsMild reactions include:nausea , vomiting, headache, itching, flushing and mild skin rash or hives.Moderate reactions include:severe skin rash or hives, wheezing, abnormal heart rhythms, high or low blood pressure and shortness of breath or difficulty breathing.Severe reactions include:difficulty breathing, cardiac arrest, swelling of the throat or other parts of the body and convulsions.A very small percentage of patients may develop a delayed reaction with a rash which can occur hours to days after an imaging exam with an iodine-based contrast material. Most are mild, but severe rashes may require medication after discussion with your physician.
26. CT vs X-RAY An X-ray is built to examine dense tissues, while a CT scan is better able to capture bones, soft tissues and blood vessels all at the same time. X-ray equipment is much smaller and less complex than a CT scan since a CT scanner needs to rotate around the patient being scanned.X-ray may identify an abnormality, but a CT scan should be able to show the exact location and examine the nature of a formation.X-ray provides a 2D image, while a chest CT scan is able to produce a 3D view of your organs.X-ray is a good low-cost, to compare with CT scan.
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32. The Kidneys Pre-contrast Post-contrast cortex Renal pelvisRenal veinIVC Aorta
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34. Barium Sulfate Contrast Materials in CT-Scan
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