What is a cardiac CT scan?
A cardiac CT scan of the heart is an imaging method that uses X-rays to create detailed images of the heart and its blood vessels.
However, unlike a traditional angiogram, which is an advanced X-ray of the arteries, the color is inserted into a small vein in the hand rather than the artery in the groin. You may also be given certain medications to slow your heart rate, which will make taking pictures easier.
- This test is called a coronary calcium scan to see if there is calcium in your arteries.
- This is called a CT angiogram if it looks at the arteries that carry blood to the heart. This test assesses whether these arteries are narrowed or blocked.
- Tests sometimes look for problems with these structures along with scans of the aorta or pulmonary arteries.
When a cardiac CT scan is necessary?
A cardiac CT scan may be helpful if your cardiologist thinks you may not have coronary artery disease, but cannot explain what is causing your symptoms. Therefore, it is often used to rule out coronary heart disease rather than check for it. It is also helpful if you have a heart attack but your doctor doesn’t know why.
If your doctor thinks you have coronary artery disease, they are more likely to do a traditional angiogram.
Another reason you may need a coronary CT angiogram is if your doctor suspects that you have an abnormality in the structure of your heart.
Purpose of cardiac CT scan
A cardiac CT scan is a non-invasive procedure that is ideal for monitoring a patient with low-risk heart problems or symptoms of coronary artery disease. Doctors also use a cardiac CT scan to check for blockages and damage to the coronary arteries.
Doctors may request that patients undergo a cardiac CT scan before or after other coronary procedures.
A cardiac CT scan is a relatively low-risk procedure because it is non-invasive, rather than injected through the manual cannula.
During a cardiac CT scan, patients are exposed to more radiation than a normal X-ray because multiple images of the heart are taken, although the dose is usually lower than that of a standard coronary angiogram. Even if low doses of radiation are used, any radiation may slightly increase the risk of cancer in the future. The risk is slightly higher in younger patients.
Some people are allergic to the opposite and it is much higher if you have multiple other serious allergies. Allergic reactions to X-ray dye are usually mild and can be treated with medications.
There is a very small risk that patients will experience a severe reaction to the contrast medium and will experience:
- Low blood pressure
- Anaphylactic shock
- Cardiac arrest
How cardiac CT scan is performed?
The cardiac CT scan is performed in the radiology department of the hospital or in a clinic that specializes in diagnostic procedures.
You will be given a beta-blocker before the scan. These drugs slow down your heart so that clearer pictures can be taken. Small, sticky discs called electrodes are placed on your chest to record the scan. The radiology technologist inserted an intravenous (IV) line into a vein so they could inject radioactive dye into your hand. You may feel a short or hot boil or a temporary metallic taste in your mouth when you inject the dye.
Before your cardiac CT scan, it is important to follow these instructions:
- Fast for at least 4 hours
- Sips of water may be taken
- No smoking for at least 2 hours
- No vigorous exercise for at least 4 hours
- Avoid tea and coffee for at least 12 hours
Day of your cardiac CT scan,
- Six hours before the test: do not eat anything that contains caffeine.
- You can have breakfast and/or lunch. Drink water before your appointment.
- Do not take metformin if you are taking it.
- Take your other common medications unless prescribed by your doctor. Bring all your medications in the original bottles.
Before scanning, your heart must beat at a certain rate to ensure a correct diagnostic result. You may need to be given medication at your appointment if your heart rate is not at the required level. It comes in a tablet form called a beta-blocker. The radiographer performs pre-scan examinations, which determine it.
After cardiac CT scan
- The ECG monitor and cannula are removed and you are asked to change your clothes again
- If you have a beta-blocker, you will be asked to stay in the section for about 20 minutes for observation
- You can go back to eating/drinking normally
- You are advised to drink plenty of water within 48 hours after the scan to remove the color injection from your body
The cardiac CT scanner has a large opening that passes through a flat platform or table. Some call this opening the “donut hole.” The patient was lying on the table while scanning. When the machine is turned on, a donut-shaped X-ray tube from the machine rotates rapidly and the patient moves through it. X-rays pass through the patient at different angles and hit special detectors. Images taken during the scan produce cross-sectional or three-dimensional views of the heart and blood vessels in less time.
Specialists who handle cardiac CT scan
- Department of Cardiology and Cardio surgeons