CAD-RADS — What It Means on Your Imaging Report
Quick Answer
CAD-RADS (0–5) is a scoring system used on coronary CT angiography (CCTA — a CT scan of the heart's arteries that uses contrast dye) to grade the worst stenosis (narrowing of the artery) in the coronary arteries — the number guides whether more testing or treatment is needed.
What Is CAD-RADS?
CAD-RADS stands for Coronary Artery Disease Reporting and Data System. It was developed jointly by the American College of Radiology (ACR) and the Society of Cardiovascular Computed Tomography (SCCT) so that every radiologist describes coronary CT angiography findings the same way and recommends the same next step. The current version is CAD-RADS v2.0, published in 2022.
CAD-RADS is used on coronary CT angiography (CCTA) — a CT scan of the heart's arteries that uses contrast dye to see if the arteries that feed the heart muscle are narrowed by plaque (fatty buildup on the inside wall of the artery). The score grades the highest-grade stenosis (the worst narrowing) found in the coronary arteries, on a scale from 0 to 5.
The number itself is not a diagnosis of a heart attack. It is a structured way to express how narrowed the worst spot in the coronary arteries looks on imaging, and to point to a clear next step — from prevention, to extra testing, to a hospital procedure.
Categories / Classification
| CAD-RADS Category | What It Means | Recommended Action |
|---|---|---|
| 0 | No visible plaque or narrowing in any coronary artery | No further cardiac imaging is needed for narrowing. Focus on general heart-disease prevention based on your risk factors |
| 1 | Minimal narrowing (1–24%) in the worst spot — plaque is present but does not narrow the artery much | No further cardiac imaging is needed for narrowing. Lifestyle changes and risk-factor control are the usual next step |
| 2 | Mild narrowing (25–49%) in the worst spot | No further cardiac imaging is needed for narrowing. Preventive treatment — for example, statins based on your risk — is commonly recommended |
| 3 | Moderate narrowing (50–69%) in the worst spot | Functional testing (tests like a stress test that check how well your heart works under load) is often considered, along with preventive treatment, to decide next steps |
| 4 | Severe narrowing. 4A: 70–99% narrowing in one or two coronary arteries. 4B: left main artery (the main artery on the left side of the heart, which feeds a large area) ≥50%, OR three-vessel ≥70% | Referral to a heart specialist. Invasive coronary angiography — a thin tube threaded into the heart's arteries to take detailed pictures — is often next, sometimes followed by revascularization (opening the artery with a stent or bypass surgery) |
| 5 | Total occlusion (100%) — a coronary artery appears completely blocked on imaging | Urgent referral to a heart specialist. Invasive coronary angiography is typically the next step, often followed by revascularization with a stent or bypass surgery |
CAD-RADS v2.0 also adds a plaque burden score (P1–P4) — a separate score for how much plaque is present overall — and modifiers:
- HRP (high-risk plaque) — plaque with features that raise the chance it could cause a heart attack.
- ISR (in-stent restenosis) — new narrowing inside a previously placed stent.
- G (graft) — flags findings on a bypass graft rather than a native artery.
- E (exception) — image quality was limited but the radiologist could still give an assessment for some segments.
- N (non-diagnostic) — image quality was too poor to assess.
When You Might See This on Your Report
You will see CAD-RADS only on one type of scan:
- Coronary CT angiography (CCTA) — a CT scan of the heart's arteries that uses contrast dye, typically ordered to evaluate chest pain or to check the heart's arteries in people at intermediate risk for coronary artery disease
The CAD-RADS category usually appears in the Impression section of the report, next to the description of the coronary arteries. Any modifiers (HRP, ISR, G, E, N) are written right after the main number — for example, "CAD-RADS 3/HRP".
Should I Be Worried?
It depends on the category, and the most common worry is around CAD-RADS 3 and 4.
- CAD-RADS 0–2 do not need an invasive procedure. These scores mean no plaque, minimal plaque, or mild narrowing. The usual next step is preventive care — lifestyle changes and, depending on your risk, medicines like statins.
- CAD-RADS 3 is intermediate. The worst narrowing is moderate (50–69%). Your doctor often adds functional testing — tests like a stress test that check how well your heart works under load — to decide whether the narrowing is causing real trouble for the heart muscle before considering a hospital procedure.
- CAD-RADS 4 and 5 carry a higher chance that an artery is significantly narrowed or fully blocked. The usual next step is invasive coronary angiography — a procedure where a doctor threads a thin tube into the heart's arteries to take detailed pictures — sometimes followed by revascularization (opening up the artery with a stent or bypass surgery). The score grades the imaging, not the diagnosis of a heart attack — a CAD-RADS 4 does not mean you are having a heart attack right now.
- Modifiers can shift the picture. For example, a CAD-RADS 2 with the HRP modifier (high-risk plaque) tells your doctor that even though the narrowing is only mild, the plaque has features that raise the chance it could cause a heart attack — and that may change how aggressively prevention is managed.
What Should I Do Next?
- Find the CAD-RADS number in the Impression section of your report (for example, "CAD-RADS 2" or "CAD-RADS 4A/HRP") and write it down exactly as it is written, including any modifiers.
- Ask the doctor who ordered the scan to walk you through the specific number for your case, and to translate the percentage of narrowing into plain language.
- Clarify which path applies to you — preventive care for 0–2, functional testing for 3, or invasive coronary angiography with possible revascularization for 4–5 — and ask about timing for the next step.
- If any modifiers are listed (HRP, ISR, G, E, N), ask what they mean for your plan. For example, HRP can lead to stronger preventive treatment even at low main categories, and N may mean the scan has to be repeated.
- Consider asking for a referral to a cardiologist (a doctor who specialises in heart conditions) if you have CAD-RADS 3, 4, or 5, so the right specialist is involved in deciding between functional testing and an invasive procedure.