Imaging
CT Angiogram
A CT angiogram uses a CT scanner and an injection of contrast dye to produce detailed pictures of your blood vessels, looking for narrowing, blockages, aneurysms or other problems.
Quick answer
CT Angiogram: what it is and what the results mean
A CT angiogram (CTA) combines a computed tomography (CT) scan with an injection of iodine-based contrast dye. As the dye passes through the arteries and veins, the scanner takes cross-sectional images that are reconstructed into detailed 3D maps of the blood vessels.
- Why it is done: It is used to look for narrowed or blocked arteries (for example in the heart, brain, legs or kidneys), aneurysms (bulges in a vessel wall), blood clots, and abnormal blood vessels before surgery or other treatment.
- Understanding results: A radiologist examines the images and sends a report to your doctor.
What it is
A CT angiogram (CTA) combines a computed tomography (CT) scan with an injection of iodine-based contrast dye. As the dye passes through the arteries and veins, the scanner takes cross-sectional images that are reconstructed into detailed 3D maps of the blood vessels.
Why it is done
It is used to look for narrowed or blocked arteries (for example in the heart, brain, legs or kidneys), aneurysms (bulges in a vessel wall), blood clots, and abnormal blood vessels before surgery or other treatment.
What to expect
A thin tube (cannula) is placed in a vein, usually in the arm, to give the contrast dye. You lie on a table that moves through the ring-shaped scanner while it takes pictures; the dye can cause a warm flush or metallic taste for a few seconds. The scan itself usually takes only a few minutes.
Understanding the results
A radiologist examines the images and sends a report to your doctor. Results show whether the vessels are healthy, narrowed, blocked or bulging, which guides decisions about medicines, procedures or surgery.
Good to know
Risks and limitations
CTA uses X-ray radiation and iodine contrast, which can rarely cause an allergic reaction or affect the kidneys — you may have a blood test to check kidney function first. Tell staff if you are or might be pregnant or have had a contrast reaction before.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
CT Angiogram: frequently asked questions
Is a CT angiogram the same as a normal angiogram?
A CT angiogram is non-invasive and uses a CT scanner with a dye injection into a vein. A traditional (catheter) angiogram threads a fine tube into an artery, so a CTA is often used first as a less invasive alternative.
Do I need to prepare for a CT angiogram?
You may be asked not to eat for a few hours beforehand and to avoid caffeine before some heart scans. You will usually have a kidney blood test, and should tell staff about allergies, diabetes medicines and pregnancy.
Related tests
Other imaging investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- Royal College of Radiologists / relevant professional body
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