Imaging
Angiogram
An angiogram is a test that uses dye and imaging to show the blood vessels, most often the arteries of the heart. It reveals narrowings or blockages.
Quick answer
Angiogram: what it is and what the results mean
An angiogram uses a contrast dye and X-rays (or CT/MRI) to make blood vessels visible. A coronary angiogram, which looks at the heart’s arteries, is one of the most common types.
- Why it is done: It is used to look for narrowed or blocked arteries — for example in angina or after a heart attack — and to plan treatments such as stents or bypass surgery, as well as to assess vessels elsewhere in the body.
- Understanding results: The images show where arteries are narrowed or blocked and how severe this is, guiding whether medicines, a stent or surgery are needed.
What it is
An angiogram uses a contrast dye and X-rays (or CT/MRI) to make blood vessels visible. A coronary angiogram, which looks at the heart’s arteries, is one of the most common types.
Why it is done
It is used to look for narrowed or blocked arteries — for example in angina or after a heart attack — and to plan treatments such as stents or bypass surgery, as well as to assess vessels elsewhere in the body.
What to expect
For a coronary angiogram, a thin tube is passed from a vessel in the wrist or groin to the heart under local anaesthetic, and dye is injected while X-ray images are taken. It usually takes 30–60 minutes; some newer angiograms use only a CT scan.
Understanding the results
The images show where arteries are narrowed or blocked and how severe this is, guiding whether medicines, a stent or surgery are needed. The cardiologist explains the findings and the recommended plan.
Good to know
Risks and limitations
A catheter angiogram is generally safe but, being invasive, carries small risks such as bruising, bleeding or, rarely, more serious complications. Contrast dye can occasionally cause reactions or affect the kidneys, so staff check for allergies and kidney problems first.
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
Angiogram: frequently asked questions
Is an angiogram a major procedure?
A standard coronary angiogram is usually a day-case test done under local anaesthetic, not major surgery. It is invasive, so there are small risks, which your team will explain beforehand.
What is a CT angiogram?
A CT angiogram uses a CT scanner and injected dye to image the arteries without passing a tube into the heart. It is less invasive and is increasingly used to assess coronary arteries.
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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