What Is a CT Cardiac Angiogram (CTCA)? | Epoch Medical Imaging
CT Cardiac Angiogram (CTCA) at Epoch Medical Imaging, St Ives. Non-invasive coronary artery imaging. Serving the North Shore — Turramurra, Pymble, Gordon & surrounds.
How a CTCA Visualises the Coronary Arteries Without Invasive Catheterisation
A CT Cardiac Angiogram (CTCA) is a non-invasive scan that produces detailed images of the coronary arteries — the blood vessels that supply the heart muscle with oxygen-rich blood — without the need for any incisions, catheters, or arterial punctures.
How it works:
– An intravenous (IV) cannula is placed in your arm — the same as for a routine blood test or drip.
– A contrast dye (iodine-based) is injected through the IV during the scan to make the coronary arteries clearly visible.
– The CT scanner — a ring-shaped machine that you pass through — acquires very high-resolution images of the heart and coronary arteries over just a few seconds of scanning time.
– The images are reconstructed by specialised software into detailed three-dimensional representations of the coronary arteries, allowing the radiologist to assess their walls, any plaque deposits, and the degree of any narrowing.
The entire process is completed in a single outpatient appointment at Epoch Medical Imaging in St Ives — providing your cardiologist or GP with the coronary artery information they need without the recovery time or procedural risks of an invasive angiogram.
CTCA vs Invasive Coronary Angiogram: Key Differences
A CTCA and a traditional invasive coronary angiogram both image the coronary arteries — but they differ fundamentally in how they achieve this, and in their respective risks and benefits.
For most patients who need coronary artery assessment for diagnostic purposes — without a planned intervention at the same time — CTCA provides equivalent or better anatomical information with far less risk and inconvenience. Traditional invasive angiogram is reserved primarily for situations where coronary intervention (such as stenting) may be performed in the same session.
What Can a CTCA Detect — Plaques, Stenosis & Anomalies?
A CTCA provides uniquely detailed information about the coronary arteries — both their inner lumen (the channel through which blood flows) and their walls (where plaque accumulates).
What a CTCA can detect:
– Coronary artery plaque: Both calcified (hard) plaque and non-calcified (soft) plaque within the artery walls — plaque is the fundamental pathology of coronary artery disease.
– Coronary artery stenosis: Narrowing of the coronary artery lumen due to plaque build-up — assessed as a percentage of luminal narrowing.
– Coronary artery calcium: The amount and distribution of calcified plaque — contributing to the coronary artery calcium (CAC) score.
– Coronary anomalies: Congenital variations in coronary artery anatomy that may have clinical significance.
– Heart chamber structure: The size and appearance of the heart chambers and major vessels.
– Non-coronary cardiac findings: The pericardium, great vessels, and adjacent chest structures visible on the scan.
The combination of luminal and wall information makes CTCA uniquely powerful — it can identify significant coronary plaque even when the lumen appears only mildly narrowed, identifying risk before significant obstruction has developed.
Radiation Dose & Contrast Dye in a CTCA
Understanding the two key technical aspects of a CTCA — radiation dose and contrast dye — helps patients make informed decisions and prepare appropriately.
Radiation dose:
– A CTCA involves a moderate radiation dose — higher than a standard chest X-ray, but modern cardiac CT technology has dramatically reduced the dose required compared to older scanners.
– At Epoch Medical Imaging in St Ives, we use the lowest dose compatible with diagnostic image quality — following the ALARA (As Low As Reasonably Achievable) principle.
– The diagnostic benefit of a CTCA — potentially identifying or excluding significant coronary artery disease — typically far outweighs the associated radiation dose for appropriate patients.
Contrast dye:
– An iodine-based contrast injection is essential for a CTCA — it is what makes the coronary arteries visible.
– The contrast is given through an IV drip in the arm.
– Most patients tolerate the contrast very well. You may feel a brief warm flush throughout your body — this is normal and passes within a minute.
– Patients with kidney impairment or a history of contrast reactions require individual assessment before proceeding — our team will review this when you book.
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