Every two minutes in the UK, someone has a heart attack. Coronary heart disease is this country’s biggest killer. If you have problems with your heart, or you’ve been referred to a specialist by your doctor, you may have to go for a heart scan. This is a simple, non-invasive assessment and helps detect heart disease early, thus reducing the potential for illness and minimising risk factors.
There are many different types of heart scan and many different names for them. Three of the most common are reviewed here.
This article on heart scan is written by Jackie Griffiths, a freelance journalist who writes health, medical, biological, and pharmaceutical articles for national and international journals, newsletters and web sites.
Ultrasound heart scan
An ultrasound heart scan (also known as a sonograph) uses very high-frequency sound waves to create accurate images of the structure of the heart and the way it’s working. This procedure is used on pregnant women to show them their unborn babies, and is completely safe.
The way this type of heart scan works is to direct high-frequency sound waves towards the heart, which will bounce off solid objects but pass through liquid and soft tissues. Gel will be placed onto your chest and a probe will be gently moved over the area in order to give several of different viewpoints. A moving image of your heart, and the valves within them, is created using these bounced back echoes, which the doctor can see on a screen. This is called an echocardiogram (ECG).
An ECG heart scan can provide doctors with the following information:
- The size of the heart chambers
- The dimensions or volume of the cavity, and the thickness of the walls
- How the heart muscle is working and if there is any disease
- In patients with long-standing hypertension or high blood pressure, an ECG heart scan can determine the thickness and “stiffness” of the ventricle walls
- Whether there is any ventricle enlargement and how severe it is
- The response to treatment over time
- The pumping function of the heart
MRI heart scans
MRI stands for Magnetic Resonance Imaging, which is a technique that produces detailed pictures of the internal organs of the body. When used to examine the heart, it is called a cardiac MRI, and can also show the blood vessels and arteries that surround it, and how blood flows through it. This type of heart scan is useful when investigating congenital abnormalities or conditions such as cardiomyopathy and coronary heart disease.
When you have an MRI, you are required to lie down, still, inside a tube or small tunnel, while short bursts of magnetic fields and radio waves are created around you. This will allow the doctor to have a clear picture of your heart and the way it’s working. An MRI is painless, although it can be noisy, and if you suffer from claustrophobia you may find it difficult. The whole test takes about an hour. If you have a pacemaker or implantable cardioverter defibrillator (ICD) you will not be able to have an MRI. If you have any metal implants in your body, such as pins or screws, plates or eat implants etc you must notify the radiographer as you may not be able to have an MRI.
CT heart scans
Cardiac CT scans (also known as computerised tomography, CAT scans, or EBCTs) are a very sophisticated type of x-ray linked to a computer. A CT heart scan gives accurate cross-sectional views of the structures of the heart, including coronary circulation and how all the vessels are working (aorta, pulmonary veins, and arteries). It can tell if your heart muscle is enlarged, damaged, or faulty. You will probably be given an intravenous (IV) contrast dye before the scan, in order to give doctors a good view of the blood vessels on the surface of the heart.
After you’ve been given the dye through a vein in the back of your hand or arm, you will be asked to lie on a bed or table underneath the scanner - which is a large machine with a ring around the bed. Only the part of you that needs to be scanned will be underneath the ring. During the CT heart scan you will be exposed to a small amount of radiation (approximately equivalent to three year’s worth of natural radiation we’re normally exposed to in one year of life. This is considered a very low dose).