I would do mine again in a heartbeat!
To answer your question, they used live x-ray and could see where the needle was and the location of any leaks,thing's like that.
I never knew how bad things actually were (in my back). The test is nothing, they put in an IV, and when I got to the procedure room, they put a covering over my back and told me he was going to numb a couple area's and would feel like a bee sting. About the 5th one, I told him he really needed an exterminator in there for all those bee's
I never felt a needle go in. When one hit a bad disk my legs went numb (scary) but it was only for a second so don't worry, they told me it was ok.
My back went out within seconds and they instantly ask if it was the same pain or a different pain, it was the same. They quickly put versed and Demerol in my IV line. Where I went I had to stay in recovery for 8 hours, I decided to take a nap, but my hip wouldn't stop hurting so they gave me 2mg of morphine, I turned onto my side, fell asleep, woke up a few hours later to a turkey & cheese sandwich with all the toppings, chips, sliced peaches and 2 soda's. I told them I was fine and going home, it was 7 hours, but said it was ok and helped me off the gurney to get dressed, a bit wobbly from the drugs, but able to walk to the bathroom, get dressed and ride home, I also had a script for home.
The whole test doesn't take more than 10 minutes. They do a CT Scan to see how much dye is leaking if any.
There are alot worse tests, But this one is worth it.