YouTube - MRI - Loose Grad Cables Flapping
2007/09/14/1654RTFA: http://www.youtube.com/watch?v=ORxRpd2RqqU&NR=1
This video was taken during an MRI scan. A scanner was installed in an old trailer without securing the grad cables!! They are hanging vertically at the back of the magnet, flapping in the magnetic breeze. This caused HUGE artifacts, both from spiking and from temporal variations in the main field and gradient fields giving the appearance of very bad eddy current compensation. Of course, eddies measured fine under the low power conditions of the eddy current compensation protcols.
Look at them fly.