What it means
CAD-RADS is used on coronary CT angiography, a CT scan of the heart's arteries with contrast. It sums up the worst narrowing (stenosis) found. 0 means no plaque or narrowing, and 1 minimal narrowing (1 to 24 percent). 2 is mild (25 to 49), 3 moderate (50 to 69) and 4 severe (70 to 99). 5 means an artery is fully blocked. N means the scan could not be fully assessed.
When it matters
A 0 makes significant artery disease very unlikely. 1 and 2 show plaque without a significant blockage, and the focus is usually prevention, such as cholesterol and blood pressure. 3 may lead to a stress test or another test of blood flow. 4 and 5 usually lead a cardiologist to consider further tests, such as a catheter angiogram. 4B means the left main artery or all three main arteries are significantly narrowed. P1 to P4 describe plaque amount.
Questions to ask your doctor
- Which artery has the worst narrowing, and how severe is it?
- Do I need a test to see if the narrowing limits blood flow?
- What does the label after my category, such as P2, mean?
