Why in the wide, wide world of sports are MRI machines so loud?

Are there evil garden gnomes hammering away inside them?

You’re complaining about a little tapping? Tsk. You need to be a big girl.

http://www.amerasekera.freeserve.co.uk/mri.html

"What happens during the procedure?

The patient is comfortably positioned on a special table which slides into the MRI system opening where the magnetic field is created. Then the radiologist and technologist leave the room and the individual MRI sequences are performed. The patient will hear tapping noises during the examination. The tapping is created when magnetic field gradient coils are switched on and off to measure the MRI signal reflecting back out of the patient’s body."
etc. etc.
…or was it this machine you’re talking about.

http://dem0nmac.mgh.harvard.edu/forum/SpinalDisordersF/KathyDontFearTheMRI.html

“The loud ones sound like a monkey on the loose running around the machine banging on the sides with a pipe wrench,”

I can vouch that some MRI machines are very loud. Also, the sound is irregular, which isn’t conducive to ‘Tuning it out’.

“OK, now lie very still, and don’t jump at the sudden loud noises we will be subjecting you to.”

Monkey with a pipe wrench? Nah. More like someone firing a machine gun, at the other end of the submarine.

I hear they now have ‘open’ MRIs, which aren’t so claustrophobia inducing.

I always liked showing up to the Imaging center, and announcing: “I’m here to have all the hydrogen atoms in my brain aligned.”

Comfortably? COMFORTABLY? HA! I’ve had MRIs. While I was in no pain, I wouldn’t say that such procedures, or the tables associated with them, are comfortable.

I am a very big girl: 6’0", with a deep manly voice.

Your response was informative. However, it begs the question why does switching the magnet(s) on and off make so durn much noise?

The electromagnets in an MRI consist of coils of wire wrapped around piece of metal. When the electricity is switched on the coil generates a magnetic field. Since the coils have current flowing through them, they react by attempting to align themselves with the magnetic field. This causes the wires to twitch and bang into each other and make sounds like evil garden gnomes.