A CT coronary angiogram is a detailed scan of the heart arteries that takes minutes and is one of the best ways to rule out narrowing. The most uncomfortable parts are usually the cannula, the contrast flush, and a brief breath hold.
CTCA is an anatomy test. It shows whether plaque is absent, present without major narrowing, or causing a narrowing that needs review.
What happens during the appointment
Move through the steps to see what may happen and what you may feel.
Preparation selected.
Preparation
What happensThe team checks your details, medicines, allergies, kidney history and pulse. You may be asked to avoid caffeine; follow your appointment letter.
What you may feelMostly waiting, questions and monitoring. ECG stickers may feel cool and slightly sticky on the skin.
The cannula
What happensA small plastic tube is placed into a vein so contrast can be injected for the artery pictures.
What you may feelA sharp scratch, then pressure or taping at the cannula site. Tell the team if it becomes painful.
Beta blocker
What happensIf your pulse is faster than ideal for clear pictures, the team may give a beta blocker to slow the heart. Not everyone needs it.
What you may feelYou may feel no different, or notice the pulse settling. The team checks suitability first.
Contrast flush
What happensIodinated contrast goes through the cannula so the heart arteries show clearly on the scan.
What you may feelA brief warm flush, a metallic taste, or a sensation like passing urine. These feelings usually pass quickly.
Breath hold
What happensThe scanner asks you to keep still and hold your breath while the table moves and the pictures are taken.
What you may feelThe scanner is close around your chest but open at both ends. The breath hold is brief, and the staff can speak to you.
Afterwards
What happensThe cannula is removed and the scan is checked. The formal report goes back to the team or clinician who requested it.
What you may feelMost people feel back to normal quickly. Ask the scan team what local advice applies afterwards.
What the result can say
- Normal arteriesThe scan has not shown plaque or narrowing in the arteries assessed. Your clinician still fits this to your symptoms.
- Non-obstructive diseasePlaque is present, but it is not described as causing a major blockage. This may lead to prevention and risk-factor discussion.
- Obstructive diseaseA narrowing is described as potentially important. Your clinician may consider further tests, medicines, or a treatment discussion.
- Calcium scoreThis describes calcified plaque. A higher score means more calcified plaque, interpreted with age, risk factors, symptoms and the CTCA pictures.
Tell the scan team before the day
Contact the radiology booking team or the clinician who requested the scan if you have had a previous reaction to iodinated contrast, severe kidney disease, possible pregnancy, difficulty lying flat, or worries about medicines you were asked to pause.
Do not change tablets from this page; follow the instructions from the team arranging the scan.
Radiation and contrast
CTCA uses x-rays, so there is radiation exposure. Modern scan protocols are designed to keep the dose as low as possible while still producing diagnostic pictures.
The contrast dye makes the artery pictures clear. The team screens for allergy and kidney-risk issues because contrast is usually straightforward, but it is not ignored.
Evidence
Guidelines and reporting standards support CTCA as a structured anatomical test: scan teams optimise heart rate, contrast and image quality; reports describe plaque, narrowing and calcium; and the result is interpreted with the clinical story.
Sources: SCCT coronary CTA acquisition guideline, doi:10.1016/j.jcct.2016.10.002; CAD-RADS 2.0 reporting standard, doi:10.1016/j.jcmg.2022.07.002; ESC chronic coronary syndromes guideline, doi:10.1093/eurheartj/ehz425; SCOT-HEART CTCA follow-up, doi:10.1056/NEJMoa1805971.
Would you like specialist advice?
I offer face-to-face appointments, normally 30 minutes, at the Finchley Road clinic.