> > I'm not sure what a MRI machine is, do you know how it's called in french?
>
> No, but I know what it stands for in English: Magnetic Resonance Imaging. It uses magnets to take pictures of your insides... somehow.
>
> We need a scientist and speaker of French and English here, stat(whatever that's short for)! :-)
>
The Scientist

okay, my scientific viewpoint: I'm doing an honours thesis using the only 3Tesla MRI in the southern hemisphere...

The nucleus of atoms have an Electromagnetic pole. By putting a strong magnetic field round someone, you align all the poles, giving a certain signal.

Now you pass a radio-pulse through them. This is not harmful, radio waves pass through your body all the time, an dhave been doing so since before you were born. This radio pulse 'dephases' the nuclei, which sort of flips them on their side. Once it has passed, they flip back, but they all flip back at different speeds, depending on what's surrounding them. We measure hydrogen for the images, because there's heaps of them in the body. So hydrogen nuclei surrounded by kidney proteins flip back at a different speed to hydrogen nuclei surrounded by interstitium proteins, hence giving a variation of signal which is measured, and translated into a picture.

Our MRI can measure differences to 1 millimetre, even smaller, so it's kinda accurate.

hope this helps :oP
samhael