I've had a pulmonary angiogram, if that helps. NHS UK. (It is like the ct angiogram described in the link)
I had to undress and put on a hospital gown. A nurse asked me several questions in particular whether I had had a procedure where a contrast dye had been used. I hadn't. Very rarely there can be a reaction but any reaction can be dealt with so nothing to worry about. I had no reaction.
A cannula was inserted into a vein at my elbow which was to be used to insert the dye. I was warned that I might feel a flushing sensation as the dye was inserted, and I might feel the need to pee ( but I wouldn't, it's just a sensation, nothing to worry about.)
Then I was taken into the lab, lay on my back, contrast inserted and I was slid into the machine. I noticed a flushing but it was not unpleasant and quickly over. Several images were taken, perhaps about 10 minutes.
No pain. I was glad the nurse explained what would happen.They were checking my lungs for why I get so breathless and my result was fine which was reassuring.
I hope this reassures you
@Dechi. Since mine was a pulmonary angiogram, I've added a link to the British Heart Foundation page where they focus on the heart.
https://www.bhf.org.uk/heart-matters-magazine/medical/tests/angiogram
ETA: it did not hurt and I went straight home.
@Dechi -I read your post again. If reading online makes you nervous, don't look at the link but I found it reassuring and the CT angiogram it describes was just like the procedure I had. It also describes another type of angiogram. It describes it as a common test. I find keeping that in mind always helps me.
ETA2: bit inside brackets on line 1/2