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Old 06-17-2009, 08:20 PM
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MRI noise - Why do they have to be so F*CKIN' LOUD?

Just had an MRI, and during the 90 minute torture session, I had much time to think.. and try as I might, I couldn't come up with a valid reason for the machine to be so loud as to require earplugs and still give you a ringing headache.

It seems that each test or picture has its own little pattern of beeps, grinds, whistles, and clatter. Can't they just turn the damn sound off and let the technician run the show from the room?

Oh, and I love the "Don't move, or we start over" bullshit. I have an itch! I have to go to the bathroom!

MRI's suck ass.

But my question still stands. Why so loud?
Old 06-17-2009, 08:55 PM
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From what I read some of the noise is the big magnets moving around.
Old 06-17-2009, 09:14 PM
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Wikipedia has this, although it's not exactly clear.

http://en.wikipedia.org/wiki/Magneti...Acoustic_noise

"Switching of field gradients causes a change in the Lorentz force experienced by the gradient coils, producing minute expansions and contractions of the coil itself"
Old 06-17-2009, 11:04 PM
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Quote:
Originally Posted by Stink Fish Pot View Post
Just had an MRI, and during the 90 minute torture session, I had much time to think.. and try as I might, I couldn't come up with a valid reason for the machine to be so loud as to require earplugs and still give you a ringing headache.

It seems that each test or picture has its own little pattern of beeps, grinds, whistles, and clatter. Can't they just turn the damn sound off and let the technician run the show from the room?

Oh, and I love the "Don't move, or we start over" bullshit. I have an itch! I have to go to the bathroom!

MRI's suck ass.

But my question still stands. Why so loud?

The sound is intrinsic to the device itself. It comes from the generation of the pulsating magnetic fields.
Old 06-18-2009, 02:34 AM
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Quote:
Originally Posted by suranyi View Post
The sound is intrinsic to the device itself. It comes from the generation of the pulsating magnetic fields.
Do you know this as fact? If this is the case, why doesn't the machine make the same noise throughout the procedure?

I'm not trying to hammer your answer... I concede it could be spot on. But even if it's so, there is no way to mute the sound?
Old 06-18-2009, 02:42 AM
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Quote:
Originally Posted by Stink Fish Pot View Post
MRI's suck ass.
There are alternative technologies for looking at what is inside your brain. And cheaper ones, morevover !
One consists in introducing electrodes through a little hole in the skull. One can do it through a big hole, too. Another one involves lots of formaldehyde, a drill, some scalpels and a slicer. Tell me which one you prefer ! I'd be glad to help.
Old 06-18-2009, 03:38 AM
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Here's an explenation from an MRI website I've used on occasion for my MRI Physics class.

Quote:
Vibrations of the gradient coil support structure create sound waves. These are caused by the interactions of the magnetic field created by pulses of the current through the gradient coil with the main magnetic field in a manner similar to a loudspeaker coil. The sounds made by the scanner vary in volume and tone with the type of procedure being performed.
Sound pressure is reported on a logarithmic scale called sound-pressure level, expressed in decibel (dB) referenced to the weakest audible 1 000 Hz sound pressure of 2´10-5 pascal (20 micropascal). Sound level meters contain filters that simulate the ear’s frequency response. The most commonly used filter provides what is called 'A' weighting, with the letter 'A' appended to the dB units, i.e. dBA.
MRI system noise levels increase with field strength. Disposable earplugs and/or headphones for the patient are recommended in high-field systems. Noise-canceling systems and special earphones are available, and active acoustic control systems were developed, e.g. softtone, pianissimo. A sequence with low noise gradient pulses is also called 'whisper sequence'.
See also Phon and Decibel.
Old 06-18-2009, 03:43 AM
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Quote:
Originally Posted by Stink Fish Pot View Post
Do you know this as fact? If this is the case, why doesn't the machine make the same noise throughout the procedure?

I'm not trying to hammer your answer... I concede it could be spot on. But even if it's so, there is no way to mute the sound?
Because the procedure isn't exactly uniform. Different things are happening throughout the procedure. And, more often than not, you are having more than one type of scan. There are T1 and T2 scans. And within those scans, there are many sequences you can do as well.
Old 06-18-2009, 09:55 AM
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Quote:
Originally Posted by Oukile View Post
There are alternative technologies for looking at what is inside your brain. And cheaper ones, morevover !
One consists in introducing electrodes through a little hole in the skull. One can do it through a big hole, too. Another one involves lots of formaldehyde, a drill, some scalpels and a slicer. Tell me which one you prefer ! I'd be glad to help.
I don't remember your user name, so if I've pissed you off somewhere down the line, I apologize. Good grief!
Old 11-21-2013, 08:31 PM
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Magnets, Schmagnets

I have had various MRIs over the years. Most of them have involved the dreaded tunnel. It has never really bothered me until today. Maybe it was the one and one-half hour wait before the MRI. Guess that's why they call it a waiting room. Anyway, the sound today was absolutely deafening. Are you telling me that they can build a Magnetic Resonance Imaging System and they can't build a muting system? B.S. I think it's a conspiracy. The truth is, they make it ridiculously loud so you can't possibly fall asleep. Fall asleep and you may move. Move, and it's time to start over. See? That was easy…and believable. Magnets, my ass. Oh, by the way, I still don't believe Oswald acted alone.
Old 11-21-2013, 08:40 PM
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There have been some recent developments in reducing MRI noise.

The press release doesn't say much, but it does say noise is "virtually eliminated at the source". I'm familiar with noise produced by inductors, which I'd suppose is similar in that the magnetic field physically squeezes the coils and causes them to vibrate. One solution is to reduce the peak frequencies so that the inductors are squeezed more gently. Probably GE is doing something along the same lines.
Old 11-21-2013, 10:53 PM
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zombie or no

recent thread

http://boards.academicpursuits.us/sdmb/...d.php?t=702082
Old 11-22-2013, 07:38 AM
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A question to MRI experts. I can't have an MRI scan because I had open heart bypass surgery, and apparently have a metal ring on my new Aorta. I never got around to asking what would happen if I was given a MRI. Does anyone know?
Old 11-22-2013, 09:35 AM
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I don't know, but I do know it will demagnetize a brand new MetroCard you may have bought that morning for $20 and absentmindedly stuck in your shirt pocket and forgot about. So, there's that.

And I always fall asleep in the MRI.
Old 11-22-2013, 09:43 AM
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Originally Posted by Duke of York View Post
A question to MRI experts. I can't have an MRI scan because I had open heart bypass surgery, and apparently have a metal ring on my new Aorta. I never got around to asking what would happen if I was given a MRI. Does anyone know?
I might be able to dig up a cite for this if necessary, but I know a bit about MRIs because my ex worked on them. Basically, an MRI is a massive magnet, strong enough to effect even non-ferrous metals. Depending on what metal it is, the effect could vary from getting extremely hot - not something you want internally - to being moved around, which could be very quickly lethal.

I've heard anecdotes about people with, er, "intimate" piercings that they didn't mention because they were there with their parents who didn't know about them, and major problems coming from that. Don't know if it's actually true though, but I can't imagine it would be comfortable.
Old 11-22-2013, 09:45 AM
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Quote:
Originally Posted by Duke of York View Post
A question to MRI experts. I can't have an MRI scan because I had open heart bypass surgery, and apparently have a metal ring on my new Aorta. I never got around to asking what would happen if I was given a MRI. Does anyone know?
It probably wouldn't be pretty. An example of what happens when metal is present during MRI operation:

http://simplyphysics.com/flying_objects.html
Old 11-22-2013, 09:50 AM
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Stink Fish Pot, sorry about your experience. Hopefully you won't have to have another anytime soon.

I've had a handful of MRIs, though, and I find them rather soothing and usually doze off/zone out a bit. Never found them to be that loud (even when I had a head scan) and there were no earplugs, just regular headphones through which the tech tells you when to breathe. Maybe you had older equipment?

Duke of York, chances are you would get rather torn up internally. My mom, who is a nurse, told me a story about her hospital where another patient's O2 tank, in the next room, hit the wall nearest the MRI room due to the magnetic flux. I've no doubt the story was exaggerated (aren't those machines/rooms shielded? what about pens/clipboards/electrical plugs/gurneys in the radiology room itself?) but you definitely do not want to get an MRI with your hardware. My husband forgot his wedding ring for his, and even though it's mostly gold, had to stop the procedure so he could remove it due to his hand vibrating.

ETA: Holy crap, Dorjän!!!

Last edited by Elemenopy; 11-22-2013 at 09:53 AM. Reason: identified flying objects
Old 11-22-2013, 11:04 AM
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Duke of York :

Former MRI tech here - and the simple answer is that the metal ring in/on aorta or wherever would likely experience a torque/twisting-effect when the person is placed within the field (which is always 'on'). When the various imaging sequences are begun, the changing forces of torque upon the metal can easily cause the ring to bend/move as a whole and possibly tear it out of its normal place. It is also possible to have an induced current produced in circular objects (like rings on hands or things within body like pacemaker leads that happen to have looped during placement, etc). I've had plenty of patients tell me their finger's rings (platinum, gold, titanium,whatever) got warm during scan sequences along with them feeling it trying to turn in various directions/alignments upon their finger while the field was being changed rapidly by scan parameters.

Even non-ferrous items can experience the torque of attempting to line up with the magnetic poles; an aluminum ladder I used to access top of the gantry would try to rotate in my hands as I moved it from one side of gantry to other. Rather odd feeling as one end of 10' tall ladder would be pulled more than other, but not towards magnet - just a rotation-type movement. There was one nurse who had a necklace with lots of plastic 'charms' that had some type of shiny metal 'paint' upon them, and whenever she would come to start a difficult IV in scan room, all the charms on her necklace/bracelets would turn and align in same direction but not noticeably being pulled toward gantry at all.

It is usually the torque effect that affects things first (noticeably anyways), and of course there are instances of getting ferrous stuff too close and then becoming missiles flying to the magnet. Surgical implants are always a big worry mostly due to the torque of objects trying to align with field, and if they are shaped in a loop or such then 'electrical effects' like heating of the metal from induced current are worrisome.

Hope I made some sense...
Old 11-22-2013, 11:58 AM
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Quote:
Originally Posted by Elemenopy View Post
Duke of York, chances are you would get rather torn up internally. My mom, who is a nurse, told me a story about her hospital where another patient's O2 tank, in the next room, hit the wall nearest the MRI room due to the magnetic flux. I've no doubt the story was exaggerated (aren't those machines/rooms shielded? what about pens/clipboards/electrical plugs/gurneys in the radiology room itself?) but you definitely do not want to get an MRI with your hardware. My husband forgot his wedding ring for his, and even though it's mostly gold, had to stop the procedure so he could remove it due to his hand vibrating.
My father-in-law is one of the directors of a company which makes sophisticated / sensitive metal detectors, specifically for MRI suites. MRI suites are, in theory, shielded to prevent issues with metal items outside of the suite, but some may be better than others. Within the suite, you don't want any ferrous metal, and other sorts of metal can be problems, as well. Even small items can become projectiles, or become heated by the magnetic field.
Old 11-22-2013, 03:54 PM
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When I recently had an MRI, I kept thinking, "a lot of this sounds like early Pink Floyd or Tangerine Dream!"
Old 11-22-2013, 05:18 PM
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Originally Posted by Ionizer View Post
Duke of York :

Former MRI tech here - and the simple answer is that the metal ring in/on aorta or wherever would likely experience a torque/twisting-effect when the person is placed within the field (which is always 'on').
Hope I made some sense...
Thanks, you made perfect sense, I suppose the doctors will have to make do with CT scans.
Old 11-22-2013, 06:03 PM
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Originally Posted by bunyupp View Post
When I recently had an MRI, I kept thinking, "a lot of this sounds like early Pink Floyd or Tangerine Dream!"
Some local MRI clinics* are offering to let you bring in your own CD to listen to during the procedure. Probably will soon be offering to plug in your own digital music player! So you could have Pink Floyd, or classical, or whatever. ("Sorry doctor, but I was listening to the soundtrack of a porn movie, and some parts of my body moved on their own.)

* there are several around here, and fairly open competition between them for patient's business.

Last edited by [email protected]; 11-22-2013 at 06:05 PM.
Old 11-22-2013, 06:43 PM
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I just had an MRI on Monday and it was fine. It was an "open" MRI so no tube. Instead I lay between two large horizontal discs. Imagine a 10' McD's hamburger bun with me as the all beef patty

Ok now that you have that image seared in your brain...


The nurse asked me the name of a favorite artist and turned on Pandora. I got to listen to John Prine, The Band and some other very nice music. It was quite relaxing and painfully loud.
Old 11-22-2013, 07:42 PM
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Yesterday I walked past a MRI trailer (portable MRI facility) and heard the distinct sound of a klaxon from inside. You bet I picked up my pace considering what those magnets can do!
Old 11-22-2013, 07:44 PM
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Originally Posted by Dorjän View Post
It probably wouldn't be pretty. An example of what happens when metal is present during MRI operation:

http://simplyphysics.com/flying_objects.html
I like the image titled "Chair 2"!
Old 11-22-2013, 08:54 PM
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Steophan >I've heard anecdotes about people with, er, "intimate" piercings that they didn't mention because they were there with their parents who didn't know about them, and major problems coming from that. Don't know if it's actually true though, but I can't imagine it would be comfortable.

Firstly, what the fuck is the parent of a teen doing inside the MRI suite? I can not imagine the parent being allowed past the waiting room. And secondly, what keeps them from mentioning it once they are locked in the MRI suite with the parent sitting out in the waiting room?

Or am I alone in not dragging my mom around with me into exam suites?
Old 11-23-2013, 04:52 AM
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Originally Posted by aruvqan View Post
Steophan >I've heard anecdotes about people with, er, "intimate" piercings that they didn't mention because they were there with their parents who didn't know about them, and major problems coming from that. Don't know if it's actually true though, but I can't imagine it would be comfortable.

Firstly, what the fuck is the parent of a teen doing inside the MRI suite? I can not imagine the parent being allowed past the waiting room. And secondly, what keeps them from mentioning it once they are locked in the MRI suite with the parent sitting out in the waiting room?

Or am I alone in not dragging my mom around with me into exam suites?
I don't know, as I said they're anecdotes, and could well just be scare stories. Were it to happen though, it would be at minimum very uncomfortable.
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