Coronary Tomography (Angio CT)
Angiography is routinely performed to gain knowledge about cardiac or coronary anatomy, to detect or diagnose coronary artery disease (CAD),Doctors use vascular imaging to diagnose and treat vascular diseases and conditions. Vascular examinations produce images of major blood vessels throughout the body. In some cases, contrast material is used. Doctors perform an angiography using:
- X-ray catheters
- Computed Tomography (CT)
Computerized TOMOGRAPHY uses a scanner to produce detailed images of both blood vessels and tissues in different parts of the body. During the examination, a contrasting substance is injected through a small catheter placed in the arm’s vein. The radiologist will take high-resolution CT scans as the contrast material flows through the blood vessels.
What are some common uses of this procedure?
Angiography is useful for examining the blood vessels and organs it provides in various parts of the body, including:
- Abdomen (e.g. kidneys and liver)
- Legs and feet
- Arms Hands
Doctors use CT scans to diagnose and evaluate many vascular diseases and related conditions such as:
- Clogged blood vessels
- Blood clots
- Congenital (birth-related) malformations of the cardiovascular system, including the heart
- Unregulated blood vessels, such as vascular abnormalities
- Rupture of blood vessels
Doctors also use COMPUTERIZED TOMOGRAPHY to examine blood vessels after surgery, such as:
- Identify abnormalities, such as an aneurysm, in the aorta, whether in the chest or abdomen, or in other arteries.
- Detection of atherosclerosis (plaque) disease in the carotid artery of the neck, which may limit blood flow to the brain and cause stroke.
- Identify small aneurysms or AVM – abnormal contact between blood vessels – inside the brain or elsewhere.
- Detection of plaque diseases that have narrowed the arteries on the legs and help prepare for intravascular intervention or surgery.
- Detect ing disease in the arteries in the kidneys or conceiving blood flow to help prepare for a kidney transplant or stent placement.
Guiding radiologists and interventional surgeons who repair diseased blood vessels, such as stent implantation or stent evaluation after transplantation.
- Detect ing of one or more arteries in the neck, chest, abdomen, pelvis or limbs after trauma.
- Evaluate the arteries that feed the tumor before surgery or other procedures such as chemotherapy embolism or selective internal radiation therapy.
- Determine the anatomy or division of the aorta in the chest, abdomen or main branches.
- Show the extent and severity of coronary artery disease and its effects and an intervention plan, such as coronary artery bypass and stents.
- Examine the pulmonary arteries in the lungs to detect pulmonary embolism (blood clots, such as those that travel from the veins of the leg).
- Look at congenital malformations in blood vessels, especially arteries in children (such as abnormalities in the heart or other blood vessels due to congenital heart disease).
- Evaluation of stenosis and blockage of the vessels.
How to prepare for coronary tomography
You should wear comfortable and test-friendly clothing. You may need to wear a dress during the procedure. Metal objects, including jewelry, glasses, dentures and hairpins, may affect CT scans. Leave them at home or remove them before test. You may also be asked to remove removable hearing aids and dental calendars. Women will be asked to remove bras containing metal wires.
You will not be asked not to eat or drink anything for a few hours in advance, if a disparate substance is used in the test. You should inform your doctor about all medications you are taking and if you have any allergies. If you have a known allergy to a disparate substance, your doctor may prescribe medications (usually a steroid) to reduce the risk of allergies. To avoid unnecessary delays, contact your doctor before undergoing an examination.
Also tell your doctor about any recent diseases or other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these conditions may increase the risk of negative impact.
Women should always inform their doctor and CT specialist if there is any possibility that they are pregnant.
If you are breastfeeding your baby at the time of the examination, ask your doctor how to proceed. It may be good to pump breast milk in advance and keep it within reach until the disparate substances are removed from your body, after about 24 hours of testing. However, the latest evidence from the American College of Radiology (ACR) indicates that the amount of contrast absorbed by an infant during breastfeeding is very low.
What devices are used in Angiography ?
A CT scan is usually a large cake-shaped machine with a short tunnel in the middle. You will lie on a narrow examination table that slides to and from this short tunnel. Around you, there is an X-ray tube and electronic X-ray detectors against each other in a ring. A computer workstation that processes imaging information is located in a separate control room. This is where the technician turns on the scanner and monitors your test in direct visual contact. The technician will be able to hear you and talk to you using the speaker and microphone.
How does this procedure work?
There are many similarities between traditional X-rays and CT scans. During conventional X-rays, a single X-ray beam source sends x-rays across the body. The X-ray detector panel that comes out of the body is picked up. Based on the amount of X-rays obscured by the body’s organs, the image will appear in different shades of gray. For example, white bones appear on X-rays while the air is relatively black.
For CT scans, many X-ray beam sources and sets of X-ray detectors revolve around the body at high speed. X-ray sources send several small high-energy X-rays through the body. The detectors pick up those X-rays that come out of the body. During the examination, you will lie on a table moving through the CT scanner so that X-rays can examine different areas of the body. After that, the quick computer takes the information collected from the scanner to produce images of the body. The computer processes a large amount of CT data to create 2D or 3D images of the body.
Radiologists will analyze these images using advanced computer software and high-quality monitors to detect diseases in the body.
When a contrasting substance is inserted into the bloodstream during the operation, it clearly identifies the blood vessels that are examined by making them look bright white.
How is the operation performed?
Before the procedure or on the day of the procedure, you may be asked to fill out a questionnaire to ensure your safety during this procedure. A nurse or technician will insert an IV into the vein, usually in your arm or hand. A small amount of blood is rarely pulled through a catheter or finger stick to test kidney function.
The technician starts by placing you on the CT screening table, usually lying on your back. Straps and pillows can be used to help you stay in the right position and stay still during the test.
The automatic injection pump connected to the injection will pump the contrast material at a specified rate. In some cases, especially in children and patients with fragile and small veins, contrast may be injected manually using a syringe. During the scan, the table is placed at the starting point of the imaging, and then moves during the opening of the device during the actual CT scan. A single scan takes about one or two minutes, but multiple scans may be required.
During a CT scan of the heart, ECG points (sticky patches) are placed on your chest to synchronize CT scans with your heartbeat. If your heart is beating too fast, it may temporarily slow down with medications to get clear images of the heart. If you are receiving a heart rate control medication, you will be closely monitored during and after the procedure.
You may be asked to hold your breath during the examination. Any movement, including breathing and body movements, can lead to effects on images. Loss of image quality can be similar to this camouflage that appears on a photograph taken of a moving object.
From time to time, anesthesia is required for children to maintain their stability during the survey. It will help your doctor determine if anesthesia is needed, and if so, it will arrange them. Preparation for anesthesia may include not eating and drinking for several hours before screening to prevent complications. Also, an extended document monitoring may be needed after the examination until the effect of the drug used for anesthesia disappears.
When the test is complete, you will be asked to wait until the technician checks that the images are high enough to get an accurate result. After the examination, the technician will remove the venous catheter and place a bandage on the site of the needle hole.
A fully computerized CT scan may be completed within a few seconds. However, the actual time in the scanner room may be longer, as the technician will have to put you on the table properly, check the fourth-line position, perform the initial imaging, and set up the injection pump settings with the scanner.
CT scans are rarely performed in children because they are more sensitive to radiation than adults. For children and infants, radiologists use a low dose of CT scans with dose reduction measures.
What will I test during and after the procedure?
CT scans are painless, quick and generally easy. Using multi-sector CT scans, the amount of time a patient needs to lie down is reduced.
Although the examination is painless, you may feel some discomfort from staying still for several minutes or from iv mode. If you are having difficulty staying still, too nervous, anxious, or feeling pain, you may find that a CT scan is exhausting. A technician or nurse may offer you, under the supervision of a doctor, some medications to help you endure a CT scan test.
If a different substance is used in the vein, you will feel a tingling when the needle is inserted into the vein. You may feel warm or glowing during contrast injections. You may also have a metallic taste in your mouth that will soon disappear. You may feel the need to urinate. However, this contrast effect will recede rapidly.
When you enter the CT scanner, you may see special light lines projected on your body. These lines are used to make sure you are positioned correctly. With modern CT scanners, you may hear tinnitus and clicking sounds. These occur as the internal parts of the CT scanner, which are not usually visible to you, rotate around you during the imaging process.
You will be alone in the test room during a CT scan, unless there are special circumstances. For example, sometimes a parent wearing a lead shield may stay in the room with their child. However, the technician will always be able to see you, hear you and talk to you through a built-in intercom system.
After a CT scan, the technician will remove the IV used to inject contrast material. The small hole made by the needle will be covered with a small bandage. Then you can return to your normal activities.
What are the benefits and risks?
Angiography may eliminate the need for surgery. If surgery remains necessary, it can be performed more accurately.
CT scans are fast and non-surgical and may have fewer complications than conventional vascular imaging.
Computerized TOMOGRAPHY may provide more accurate anatomical details than other vascular tests such as conventional catheter angiography and magnetic resonance imaging (MRI).
For Angiography , there is no need for general anesthesia or local anesthesia.
Cardiac CT is a useful way to detect blocked coronary arteries.
Computerized CT angiography may also cost less than catheter angiography.
No radiation remains in the patient’s body after CT examination.
X-rays used in CT scans should not have any immediate side effects.
Most patients complete CT angiography without adverse events. But there is always a slight chance of cancer from excessive radiation exposure. However, the benefit of accurate diagnosis far outweighs the risks.
If you have a history of allergy to X-ray contrast, your doctor may advise you to take special preventive medications, such as a steroid, for a few hours or a day before CT scans to reduce the chances of an allergic reaction. Another option is to undergo a different test that does not require a disparate iodine substance.
In patients at risk of kidney failure who already have problems with kidney function, iodine contrast can further damage kidney function. Check with your doctor and radiologist for more information about this risk.
If a large amount of X-ray contrast material leaks from the injected vein and spreads under the skin where IV is placed, the skin, blood vessels and nerves may be damaged. If you feel any pain or tingling sensation in this area during or immediately after the contrast material is injected, you should inform the nurse/technician immediately.
Women should always tell their doctor and x-ray specialist or Angiography if there is any chance of pregnancy.
Genetic variation manufacturers indicate that mothers should not breastfeed their babies for 24-48 hours after the contrast material is given. However, the latest evidence from the American College of Radiology (ACR) on the media indicates that the amount of variation absorbed by an infant during breastfeeding is very low.
The risk of severe allergic reaction to different iodine-containing substances is rare, and hospitals are well equipped to deal directly with similar conditions.