Radiology The most impoant sign of significance of renal aery stenosis on an angiogram is: A A percentage diameter stenosis >70% B Presence of collaterals C A systolic pressure gradient >20 mmHg across the lesion D Post stenotic dilatation of the renal aery 💡 Explanation The most impoant sign of significance of renal aery stenosis on an angiogram is: ✓ Correct Answer: B. Presence of collaterals