A CT Coronary Angiography (CTCA) is a special type of CT scan that focuses on the coronary arteries, the blood vessels that supply the heart muscle. Using X-rays and contrast dye, CTCA produces detailed pictures that help doctors detect narrowing, blockages, and calcium buildup (plaque) in the arteries.
It is widely used to evaluate chest pain and to rule out or confirm coronary artery disease (CAD) without the need for invasive procedures.
Common Indications for CTCA
Your doctor may request a CTCA to:
- Investigate chest pain or shortness of breath
- Detect or rule out coronary artery disease (CAD)
- Measure calcium buildup (plaque) in the coronary arteries
- Check stents or bypass grafts
- Assess heart risk before surgery or major treatment
- Evaluate suspected congenital abnormalities of the coronary vessels
What does a CT scanner look like?
The scanner looks like a large, doughnut-shaped machine. You’ll lie on a moving table that passes through the scanner while images of your heart’s blood vessels are taken.
What happens during a CTCA procedure?
- You’ll lie flat on your back.
- ECG leads will be attached to your chest to monitor your heart rate.
- Image quality often improves with a slow, regular heart rate. The target varies by scanner and protocol; the team may give a beta-blocker after checking for contraindications and will monitor you.
- A contrast dye will be injected through a vein in your arm to make your coronary arteries visible.
- You’ll be asked to hold your breath briefly while the scanner takes images.
Do I need to prepare for a CTCA?
Preparation is important and varies by centre:
- Follow the centre's fasting instructions; water may be allowed.
- Avoid caffeine, nicotine, or exercise for the period stated by the centre.
- Wear comfortable clothes; you may need to change into a hospital gown.
- Do not stop prescribed medicines unless instructed. Tell the team about asthma, low blood pressure, heart-rhythm problems, and recent sildenafil, tadalafil, or similar medicine because beta-blockers or nitroglycerin may be used.
Do I need a kidney test before the scan?
Kidney-function testing is based on risk factors, recent illness, and local policy rather than being required for every patient. Tell the team about acute kidney injury, chronic kidney disease, diabetes, and relevant medicines.
How long does a CTCA scan take?
The scan itself will take about 10-15 minutes. With preparation (IV line, ECG leads), the entire visit may take 30–60 minutes.
Is CTCA safe?
CTCA uses ionising radiation and iodinated contrast. Allergic-like reactions can occur and severe reactions are rare; people with acute kidney injury or severe chronic kidney disease require individual review. Heart-rate medicine or nitroglycerin may cause dizziness, low blood pressure, wheeze, or headache and is given only after safety screening. Report injection-site pain or swelling immediately.
How is CTCA different from a conventional coronary angiogram?
- CTCA: Non-invasive, uses a CT scanner and contrast dye, good for diagnosis and ruling out disease.
- Conventional Angiogram: Invasive, uses a catheter inserted through the wrist or groin, allows both diagnosis and treatment (e.g., stent placement) in the same procedure.
When should I seek urgent help?
Active or worsening chest pressure, severe breathlessness, sweating with chest pain, fainting, or pain spreading to the arm, jaw, or back requires urgent medical assessment rather than waiting for an outpatient CTCA.
Questions to ask your team
- How will CTCA change the assessment or treatment of my coronary risk or symptoms?
- Which caffeine, heart-rate medicine, nitroglycerin, and fasting instructions apply?
- Are asthma, low blood pressure, erectile-dysfunction medicines, kidney problems, or contrast reactions relevant?
Sources and further reading
- RadiologyInfo: Coronary CTA
- ACR Manual on Contrast Media
- FDA: Computed tomography benefits and risks
Conclusion
CT coronary angiography is a non-invasive way to assess coronary plaque and narrowing in appropriately selected patients. Its usefulness depends on symptoms, heart rhythm, calcium burden, image quality, and pre-test likelihood; another functional test or invasive angiogram may still be needed.