How long does it take to do an MRI?

About 20 minutes. But it dependes on what part of the body. I personally think its hard for young children to have MRI scans because you have to stay still for that whole 20 mins, but they do make you very comfortable. Its also dangerous if you wear any metal or have a metal filling or pins in your arm, but they check you beforehand for any metal. The machine makes a lot of noise so they let you listen to music or just wear headphones.