MRI's are loud.
October 13, 2012 11:35 AM   Subscribe

Will MRI machines ever get softer?

Hi all. I had an MRI(normal, not functional) of my brain yesterday on a 3T Skylar Wide-bore machine. They gave me a mirror so that I could see my feet, it was well lit, and physically I was very comfortable. The tunnel was much larger than when I got an MRI 5 years ago.

But GOSH DARN the noise! Every time they started a new scan, I jumped, even though I was expecting a loud noise and there were a few warning clicks before hand.

I know the noise is related to the magnet, but as technology progresses, will these machines ever get softer?
posted by lettuchi to Health & Fitness (7 answers total) 1 user marked this as a favorite
This previous answer addresses sound reduction attempts.
posted by Blazecock Pileon at 11:47 AM on October 13, 2012

Did you get hearing protection of any kind during the scan? That's much easier than hoping that something will be done about the noises from the scanner.
posted by Nomyte at 12:12 PM on October 13, 2012 [1 favorite]

I was given earplugs both times I had MRIs. The second time there was music playing (very loudly, so I could hear it through the earplugs) in the room around the MRI. That was in an imaging center. The first time was just me and the machine in a trailer behind the hospital.
posted by WasabiFlux at 12:31 PM on October 13, 2012

This would be an ideal application for noise canceling headphones, except that they would interfere with the MRI-- and they don't handle high frequencies well either, I've heard.

You still might be able to cancel some of the noise though, with external speakers focused at the ear by parabolic reflectors, but it would be a hard problem, and if it malfunctioned might double the noise.
posted by jamjam at 12:38 PM on October 13, 2012

Active noise-canceling, perhaps not, but passive noise muffling is very doable, especially since noise is highest outside the scanner, not directly inside the bore. Plastic doesn't interfere with imaging in most cases. It's fairly easy to pile on earplugs, muffling headphones, foam cushions, etc.

To elaborate a bit on my earlier answer: attacking the noise problem at the level of the scanner itself is definitely possible. Some scan sequences, for instance, shift the magnetostriction noise from the gradient coils into the ultrasonic range. So the noise is still very "loud," but not in audible frequencies.

However, those imaging techniques also have particular goals and applications. They're not designed with specifically medical imaging in mind, and they're unlikely to come into use with medical patients anytime soon.
posted by Nomyte at 2:12 PM on October 13, 2012 [1 favorite]

I took part in a study a few years ago where I had to do mental tasks while my head was inside an fMRI machine.

I was given both earplugs and high-quality earmuffs, and the result was quiet enough that I actually fell asleep during the 10 minute "calibration" phase after doing the tasks. From looking at an article produced from the study the machine used was a "3.0 Tesla GE Signa EXCITE scanner".

There have been several press releases and news items about pocketable and portable MRI machines in the last few years, so, yes, there is probably differences between machines, and they will get a lot smaller and probably much more quiet in the next few years. (I'm sure there is a huge market for fMRI machines small enough that they can be built into interrogation chairs.)
posted by Baron Humbert von Gikkingen at 3:08 PM on October 13, 2012

fMRI uses a much lower amplitude than traditional MRI, hence is less noisy, so it's not really a good indication.
posted by Mai2k3 at 11:08 PM on October 13, 2012

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