Heart Scan (Coronary Calcium Scan): A Proactive Look at Your Heart's Health

A quick, non-invasive, and useful check-up that gauges how much calcium-based plaque you’ve got in the arteries of your heart – giving you a precise and individual estimate of what your chances are of having a heart attack in the future. 

Overview 

More accurately termed a Coronary Artery Calcium, or CAC, Scan, a heart scan is a really sophisticated, yet non-invasive, screening test which gives a straight, measurable reading of the quantity of calcified plaque in your coronary arteries. This is a strong asset in the area of looking after your heart to prevent issues, and is meant to spot people who might have a heart attack sometime down the line, even if they aren’t feeling anything, or showing any symptoms. 

The test uses a special, rapid CT – Computed Tomography – scanner to make a series of very clear pictures of the heart. The whole thing is very quick, doesn’t hurt at all, and needs no needles or any contrast colour. It’s only there to find, and measure, calcium building up inside the artery walls of the heart. 

Having calcium in the coronary arteries is a definite, and clear, indication of atherosclerosis – the sickness which causes most heart attacks. How much calcium is found – given as a number, a ‘calcium score’ – is a strong, separate indication of what your risk is of a heart problem in the future. Your doctor will find this really useful, as it lets them make a far more individual, and correct, risk estimate than you get with the usual things like cholesterol and blood pressure numbers. 

A calcium scan can assist in working out risk for people who are only a little, or moderately, at risk, giving the vital information required to help make sensible choices about changing your lifestyle and maybe needing to take preventative drugs – such as statins – so you can take charge of looking after your heart. 

The Scientific Principles of Coronary Calcification and Risk Assessment 

To truly get why a coronary calcium scan is such a good predictor, it’s important to look at the science behind atherosclerosis – and what calcium, specifically, does in this complicated illness.  

The Lifecycle of an Atherosclerotic Plaque 

Coronary artery disease comes from atherosclerosis, a gradual disease where plaque builds up inside the walls of the arteries bringing blood to the heart. 

1. The Initial Stage: Soft Plaque: It all starts when cholesterol and fats enter the artery wall, causing inflammation to begin. At first, the plaque is soft, fatty and doesn’t contain calcium. 
2. The Process of Calcification: With the passage of years, and as atherosclerosis goes on, the body tries to mend and strengthen the chronically inflamed spots. Calcium goes into the plaque as a piece of this lengthy healing and scar-making response. Coronary artery calcium, therefore, isn’t a sign of early atherosclerosis; it’s a clear indication of a disease which has been present for a long time, and is well-established.  
3. The Total Plaque Burden: The quantity of calcium shown on a CT scan is a very trustworthy way to measure the total amount of atherosclerotic plaque you’ve built up in your arteries over the course of your life. Someone with a large amount of coronary calcium is likely to have a large amount of the more risky, uncalcified soft plaque as well. 

Why the Calcium Score is a Good Way to Foretell What Might Happen 

A coronary calcium scan doesn’t show how narrow your arteries are, or if they have stenosis. It works by finding the total amount of calcified plaque. This is a really good way to predict what will occur in the future, for a few important reasons: 

1. It Shows the Disease Directly: Unlike things that raise your risk – such as elevated cholesterol – which only imply a risk of atherosclerosis, a calcium score that isn’t zero is clear, obvious, and shows on images that the disease is already in your arteries. 
2. It Measures How Much Plaque There Is: The number you get gives a definite measure of how far the disease has gone. The bigger the number, the more plaque is there, and the greater the chance of plaque breaking and causing a heart attack. 
3. It Makes Risk Estimates More Precise: The score is a useful way to change someone’s risk category. Someone who seems to be at little or moderate risk using the usual things doctors look at, could be put in the high-risk group if their calcium score is very large, and so need more serious treatment to stop things getting worse. On the other hand, someone who is on the edge of needing a statin, might be told everything is okay and not need medicine, if their calcium score is zero. 

Understanding Your Results: What the Agatston Score Tells You 

Your coronary calcium scan gives you a number – this is your Agatston score – and this system of scoring is what doctors everywhere use as the standard. 

How the Score Comes About 

The CT scan finds any spots in the arteries of your heart which are denser than a certain point; this shows where calcium exists. Then the computer program works out the score by taking the size of each bit of calcium deposit and multiplying it by a density value. This value – a number that’s given a weight of 1 through 4 – depends on precisely how bright or dense the calcium shows up on the scan.  Finally, the scores from every calcium deposit in every artery of the heart are added together to create the Agatston score for you. 

What Your Score Means: The Risk Categories 

A score of 0: The Power of Zero 

• Interpretation: A calcium score of zero means no calcium has built up – and can be seen – in your coronary arteries. 
• Implication: This is a really good, and comforting, finding; it suggests a very small chance of a serious heart problem in the next five to ten years. Because of this, a doctor might choose not to begin, or to put off beginning, statin drugs for quite a few patients who were thought to be at moderate risk. It’s almost like a guarantee of good heart health for a while. 

A score of 1 to 100: Mild Plaque Burden 

• Interpretation: This shows a small to slight quantity of coronary plaque. 
• Implication: You do have coronary artery disease, although it’s at an early point. Your chance of a future heart attack is thought to be small, but it isn’t zero. This is a good reason to make strong changes to how you live – like your diet and exercise – and your doctor might think about beginning a small dose of a statin. 

A score of 101 to 400: Moderate Plaque Burden 

• Interpretation: This shows there is a noticeable, and clear, amount of plaque caused by atherosclerosis. 
• Implication: Your chance of a future heart problem is much higher. This result is a definite reason to start serious medical care – a statin to reduce your cholesterol and make the plaque more stable, and usually aspirin, as well as carefully managing all your other risks. 

Score Above 400: High Plaque Burden 

• Interpretation: A score of over 400 shows a very large, and severe, build-up of plaque. 
• Implication: You are at very high risk of a heart attack. Your doctor will almost certainly suggest the strongest medical and lifestyle changes. A high score could also cause your doctor to order a functional test – like a stress test – to see if any of this plaque is blocking blood flow to the heart. 

The Importance of the Percentile Rank 

Also with your actual score, the report will show you a percentile rank. That rank measures your calcium score against the scores of other individuals who are the same age and gender as you. So, if you’re in the 90th percentile, your calcium score is better than ninety percent of the people in your group. Even should your score not seem large, a good percentile rank could suggest a quicker course for the illness – and a bigger chance of trouble. 

Identifying and Treating People Who Could Develop Heart Problems 

A coronary calcium scan is a way of checking for illness – and mainly exists to prevent problems in the first place, by assisting treatment choices in people who feel fine. 

• The Best Person to Test: Someone at Moderate Risk: The test works best on people, normally aged 40 to 70, who have no signs of heart trouble, but whose chance of a heart attack in the next ten years – worked out using usual risk assessments – is somewhere in the middle, or on the edge. For these people, the calcium reading is a strong ‘decider’ which can move them into a more risky category where statin drugs will certainly do good, or a less risky group where they can safely be put off. 

Not So Useful in Other Cases: 

1. People Already Very Safe: If someone is already very unlikely to have a heart attack, using normal reasons, a calcium scan isn’t usually worth it, as it’s unlikely to show a bad result. 
2. People Already Very Unsafe: If someone is already very likely to have a heart attack – for instance, if they’ve got an existing heart disease, have had one before, or have diabetes along with other issues – then a calcium scan isn’t needed either. These people ought to be on strong treatment anyway, no matter what their calcium reading. 
3. People With Symptoms: If you are getting things like chest pains, a calcium scan isn’t what you want. You’ll need a test of what your heart does – a stress test – or a test of what your heart is – a CT scan or catheter angiogram – to find any particular blockage which is stopping blood flow. 

Crucial Things to Do Beforehand 

1. No Caffeine or Cigarettes: For a minimum of four hours prior to your scan, you have to stay away from all caffeine - that means no coffee, tea, or fizzy drinks with caffeine in them – and you should not smoke. Because both caffeine and nicotine speed up your pulse, they could cause the pictures to be out of focus. 
2. Drugs: It is normally okay to have your usual medicines on the day of the examination. 
3. Clothes: Put on easy, not-tight clothes. You’ll be asked to take off any metal things, such as chains, that are on your upper body. 

A Step-by-Step Guide to the Scan 

Here’s what happens during the scan, in order: 

1. First, you’ll put on a hospital gown. A technician will then stick some electrode pads to your chest – these go to an ECG and are needed to make the scan work with your pulse. 
2. Next, you’re going to lie down on your back on the CT scanner’s bed; the technician will be certain you’re alright. 
3. Then, the bed slides into the middle of the big, ring-shaped CT scanner. The technician will be in the room next door, but can still see and talk to you – and will have you try holding your breath for a little bit. The scan itself happens while you do this, and it’s normally no longer than ten or fifteen seconds. You won’t experience anything throughout the scan. 
4. Finally, when the pictures have been taken, the bed comes back out, the pads come off, and you can leave; the whole thing shouldn’t take more than ten minutes. 

Myths vs Facts 

Myth: A calcium scan will say whether I’m about to have a heart attack. 

Fact: A calcium scan is a check-up that works out how much you are at risk of heart trouble over the years by finding hard, chalky build-up; however, it doesn’t find soft, non-chalky build-up which is much more inclined to break and cause a heart attack. 

Myth: Getting a calcium score of zero means I have no build-up and my arteries are completely clear. 

Fact: A zero score means there’s no build-up that can be seen to be chalky, and points to a really low risk. But, small amounts of early, soft, non-chalky build-up could still be in your system. 

Myth: The radiation from the scan is very unsafe. 

Fact: A coronary calcium scan uses a very small amount of radiation – much the same, or even less, than a normal mammogram. It doesn’t need any contrast and is generally seen as a very safe thing to do. 

Myth: A calcium scan is the same as a CT angiogram. 

Fact: They are not the same tests. A calcium scan is a fast, non-contrast CT which only measures chalky deposits. A CT coronary angiogram is a longer, more detailed test, using a drip to check for narrowing or blockages in the arteries. 

A Forward-Looking Step for Your Heart’s Health 

The coronary calcium scan is a useful and quite individualised method in what doctors now have to prevent heart disease. Offering a straightforward, actual, and simple-to-grasp view of just how much plaque you have in your arteries – instead of simply the chances, statistically – it shows your arteries as they really are. The test can be extremely comforting for people who aren’t at great risk, and for those who are, it can be a very strong, altering reason to do something positive and quickly. 

The most important thing to do first is to have a proper talk with your heart doctor, or your usual GP: they can work out what your starting risk is, and help you work out whether a coronary calcium scan will help both you and the doctor to reach the most sensible choices about keeping your heart healthy over the years.