[Tharkun]

Considering they're putting a rod up your urethra which will be burning you from within, and another device up your rectum, while you're in the uncomfortable confines of an MRI scanner, I suspect local might not be something most people would be comfortable with.

[thafoobar]

Lots wouldn't be comfortable, but there's a few who'd likely be ok with it. Urethral+anal electric stimulation is a relatively known kink. There's no way to keep still in that situation though, so I'd expect anaesthesia would be necessary for that.