geeky admission time, i love MRI. i worked on them for years. the technology involved is totally amazing. T1 and T2 precession, sagittal spin, and the ability to create a superconducting magnet with cryo... just awesome stuff. you would not believe how much is going on in the other room (rack room, not control room) for a scan. they are aligning all of your molecules in a super strong homogeneous magnetic space about the size of a basketball and then 'pinging' them with an RF pulse and 'listening' for the response based on spin and time differential. and stuff.

safe, fun, and the most amazing pictures which is why i'm always so irritated that neurologists are bored. true story.