How cardiologists figure out if the arteries to the heart are narrowed

So there are lots of different ways that we can look at the heart arteries and the two key methods that we use here in this cath lab is using x-rays with dye and also using an ultrasound camera that we actually place inside the artery. This gives us two different forms of information, complementary information to help us make decisions and to make treatment choices. So an angiogram involves placing a tube into the artery of the heart and the heart is typically in the centre of the chest, dye is injected into the arteries, we can see what the lumen, that means the inner tube of the artery, looks like, and that gives us one idea, but a better idea of what the artery is actually doing is to place a very thin wire into the artery and then a camera, which is, I've got an ultrasound probe on the very end of it, and that allows us to see the artery from the inside and get a much better appreciation of what the artery is doing and if there are narrowings and what the significance of those narrowings are. Thank you.