Coronary CT Angiography Report: CAD-RADS Explained

Key Takeaways

• A coronary CT angiography (CCTA) is a non-invasive scan that uses CT and contrast dye to look for narrowing or plaque in the arteries supplying your heart.
• Most reports include a CAD-RADS score from 0 to 5, summarizing the most severe artery narrowing the radiologist found.
• CAD-RADS 0–2 means non-obstructive disease (less than 50% narrowing) and usually needs no further heart testing.
• CAD-RADS 3 (50–69%) and 4–5 (70% or more) may prompt extra tests like CT-FFR or, in higher categories, invasive angiography.
• A modern CCTA delivers roughly 1–5 mSv of radiation, comparable to a year of natural background exposure.

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If your cardiologist ordered a coronary CT angiogram, your report likely ends with a line such as "CAD-RADS 2." That short code carries a lot of meaning. This guide explains what a CCTA measures, what each CAD-RADS category from 0 to 5 means, and what your doctor is likely to recommend next — all in plain language.

What a Coronary CT Angiography Shows

A coronary CT angiography, or CCTA, is a specialized CT scan that images the coronary arteries — the vessels that supply blood to your heart muscle. You receive an iodine-based contrast dye through an IV, which makes the arteries and any blockages visible.

According to the American College of Cardiology, CCTA has become a first-line test for evaluating chest pain in many patients because it can rule out significant artery disease without an invasive procedure. The American Heart Association recognizes coronary CT as a valuable tool for assessing heart disease risk.

The scan looks for two main things: stenosis (narrowing of the artery, often from plaque) and plaque burden (the total amount of fatty and calcified buildup). If you want a deeper definition, our stenosis glossary entry explains the term in detail.

Understanding Your CAD-RADS Score

CAD-RADS stands for Coronary Artery Disease–Reporting and Data System. It was developed jointly by the Society of Cardiovascular Computed Tomography, the American College of Radiology, the ACC, and the North America Society of Cardiovascular Imaging to standardize how CCTA results are reported. The current version, CAD-RADS 2.0, was published in 2022.

Your score reflects the single most severe narrowing found in any coronary artery:

• CAD-RADS 0: No plaque or narrowing at all. Coronary artery disease is effectively ruled out.
• CAD-RADS 1: Minimal narrowing (1–24%), or plaque with no measurable narrowing.
• CAD-RADS 2: Mild narrowing (25–49%).
• CAD-RADS 3: Moderate narrowing (50–69%).
• CAD-RADS 4: Severe narrowing — 4A is 70–99% in one or two vessels; 4B involves left main disease or three-vessel involvement.
• CAD-RADS 5: At least one totally blocked (100% occluded) artery.

For context, the Cleveland Clinic notes that narrowing below 50% is generally considered non-obstructive and rarely limits blood flow on its own.

Plaque Burden, Modifiers, and What Comes Next

CAD-RADS 2.0 added a plaque burden score from P1 (mild) to P4 (extensive). This matters because even non-obstructive plaque raises long-term risk and may justify earlier preventive treatment, such as statin therapy.

Your report may also include modifiers — short letter codes that flag special situations:

• N: Non-diagnostic image quality (some segments couldn't be assessed).
• HRP: High-risk plaque features were seen.
• S: A stent is present.
• G: A bypass graft is present.

What happens next depends on your category. CAD-RADS 0–2 typically means no additional heart imaging is needed, just risk-factor management. CAD-RADS 3 may lead to a functional test such as CT fractional flow reserve (CT-FFR), which estimates whether a narrowing actually limits blood flow. CAD-RADS 4–5 often prompts referral for invasive coronary angiography. Because CCTA uses contrast dye like many other scans, our guide on MRI with contrast vs without contrast helps explain how imaging dyes work.

Frequently Asked Questions

Is a CAD-RADS score the same as a calcium score?

No. A coronary calcium score counts only calcified plaque from a quick non-contrast scan. CAD-RADS comes from a full contrast CCTA and grades actual artery narrowing, including soft (non-calcified) plaque that a calcium score misses.

Does a high CAD-RADS score mean I will have a heart attack?

Not necessarily. A higher score means greater narrowing and risk, which is exactly why your doctor uses it to guide treatment and further testing. Many people with CAD-RADS 3 or 4 are managed successfully with medication and lifestyle changes.

How much radiation does a CCTA involve?

A modern coronary CT angiogram typically delivers about 1–5 millisieverts, roughly equal to one year of natural background radiation. Newer scanners and dose-reduction techniques continue to lower this amount.

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Disclaimer: This article is for educational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for diagnosis and treatment decisions.