Different heart scans answer different questions. An echocardiogram, cardiac CT and cardiac MRI can all be useful, but they are not the same test.
Choosing the right scan depends on the symptom and the decision the result needs to guide. A scan should answer a question. It should not just add another report.
In practice, I usually start by asking what we are trying to prove or exclude. Is the concern valve disease, heart artery narrowing, heart muscle damage, inflammation, or a rhythm problem that needs monitoring rather than imaging? Different questions need different tests.
Summary
| Test | What it is best for | Common question |
|---|---|---|
| Echocardiogram | Heart pumping, valves, heart size | Is there valve disease or a reason for breathlessness? |
| Cardiac CT | Heart arteries and anatomy | Are the heart arteries narrowed? |
| Cardiac MRI | Heart muscle detail | Is there scar, inflammation, or a heart muscle condition? |
Echocardiogram: heart ultrasound
A transthoracic echocardiogram is an ultrasound scan of the heart. It is often the first scan for a murmur, suspected valve disease, breathlessness, heart failure symptoms, or some abnormal ECG findings.
Echo looks at how well the heart pumps. It also looks at valve narrowing or leaking, heart size, thickened heart muscle, fluid around the heart, and clues about pressure in the lungs. It does not use radiation.
The limitation is that image quality can vary. Lung disease, body shape and chest wall shape can make some scans harder to interpret. Echo also does not directly show the heart arteries. A normal echo does not rule out coronary artery disease.
Cardiac CT: the heart arteries
Cardiac CT and CT coronary angiography use X-rays and dye injected into a vein to make detailed pictures of the heart and coronary arteries.
This test is often used when stable chest pain could be due to narrowed heart arteries. It can show plaque, calcium and narrowing in the arteries that supply the heart.
The main trade-offs are radiation and contrast dye. Kidney function, previous dye reactions and pregnancy need to be considered. A fast or irregular heartbeat can also reduce image quality.
Cardiac MRI: heart muscle detail
Cardiac MRI uses a strong magnet and radio waves. It gives detailed pictures of the heart muscle and does not use X-ray radiation.
MRI is useful when the question is about heart muscle rather than the arteries alone. It can help after an unexplained fall in pumping function, suspected heart muscle inflammation, heart muscle disease, or possible scar from a previous heart attack.
Some MRI scans use contrast dye called gadolinium. Kidney function, implanted devices and claustrophobia need to be checked before the scan.
How the tests fit together
These tests often work together. A patient with breathlessness and a murmur may start with echo. More specialised ultrasound tests include transoesophageal echocardiography for selected structural questions and dobutamine stress echocardiography to assess the heart under controlled medication stress. If severe valve narrowing is found, CT may later help plan treatment. If the heart muscle looks unusual, MRI may help explain why.
A patient with exertional chest tightness may need a heart artery test even if the echo is normal. A patient with palpitations and a murmur may get more useful information from echo and rhythm monitoring than from CT.
Why interpretation matters
The scan report has to be matched to the person. Mild valve leakage can be an incidental finding. A moderate artery narrowing may or may not explain symptoms. A small area of scar on MRI may have very different meanings depending on the history.
This is why “the best scan” is rarely the right question. The better question is: what decision will this scan help us make?
Dr Cassar is accredited in echocardiography, cardiac CT and cardiac MRI. That is useful because the decision is not just about ordering a scan; it is about choosing the test that best fits the clinical question and then interpreting the result in context.
When to discuss heart imaging
Discuss imaging if symptoms are persistent, exertional, unexplained, or linked with an abnormal examination, ECG or blood test. Chest tightness, breathlessness, blackouts, new ankle swelling or a new murmur should be assessed in context.
The cardiology services page summarises the cardiac tests Dr Cassar can arrange privately. For appointments, details are available here.
Questions patients often ask
Which scan shows blocked arteries?
A CT scan of the heart arteries is often used to look directly at artery narrowing. Stress scans can show whether blood flow to the heart muscle is reduced. An echo does not directly show blocked arteries.
Which scan shows valve disease?
An echocardiogram is usually the main test for valve narrowing or leaking. CT and MRI can add information in selected cases.
Which scan is best for heart muscle damage?
Cardiac MRI is often the most useful test for scar, inflammation and heart muscle conditions.
Can one scan replace all the others?
No. Each scan has strengths and limits. The right test depends on the clinical question.
Do I need imaging if my ECG is normal?
Sometimes. A normal ECG does not rule out valve disease, stable heart artery disease or rhythm problems that come and go.
