I spent 23 minutes inside an MRI machine today.
“Rrrrrrrrrrrrrrr — WHAMMMM!! Ka-CHUNG Ka-CHUNG Ka-CHUNG Ka-CHUNG Ka-CHUNG Ka-CHUNG Ka-CHUNG Ka-CHUNG….” at a decibel level that you will be quite sure is equal to the noise of an old Concorde — or possibly a new space-shuttle — taking off from your backyard.
That’s how WikiAnswers.com describes the noise from an MRI machine.
OK, what makes them so darn noisy?
To understand this in reasonable detail, it’s probably best to start off with a bit about how MRI, or magnetic resonance imaging typically works.
Each hydrogen atom in your body is composed of a proton with an electron orbiting it. The proton itself is like a little magnet, with a North and South pole, and in this way resembles the earth, which also has North and South magnetic poles. You can think of a little arrow along the north-south direction as being associated with each such proton. On average, these all point in random directions.
Turning on a big external magnet, makes the arrows line up, as each proton turns so that its South pole tends to point to the North pole of the big magnet and vice versa. (Recall that opposite poles attract and like poles repel.)
Now there will be a certain energy needed to flip these little magnets around, and that energy is determined by the strength of the external magnet. If you apply suitable radio waves of the right (so-called resonant) frequency, you can supply that energy to make the flip. The proton will eventually flip back and release a radio wave and this lets you determine where it is.
So far this just tells you that you can find out that there’s hydrogen in your body. If you suitably change the strength of the magnet over the body and over time, you can change where the hydrogen atoms are “resonant” or not, and basically measure how much hydrogen is present at any given location. As you change the strength of the magnet, you change where you’re looking and a computer can reconstruct a map of where hydrogen (typically in water) is in your body. Different tissues respond slightly differently, which means you can take interesting pictures, even of things that are all basically transparent to X-rays.
The fact that the strength of the magnet has to be changed over time and position means that all sorts of things move at least a bit in response to it, and that motion makes sound – that clanging noise.
I spent 2 hours in an MRI machine the day before Thanksgiving. I tried to take a nap, but DAMN it was loud. Plus, it was cold, so I was shivering, and every time I moved, they had to redo parts of the scan.
I’m far from claustrophobic, but the MRI I had last year
was a bit unnerving, and the banging and clanging really intensified
my unease. If the nurse hadn’t climbed in there with me who knows.
It could have been worse:
http://www.inquisitr.com/15380/275-pound-woman-told-to-use-zoo-mri/
Thanks DJ, thats a pic that will stay with me for a while. UGHHH
I had an MRI a couple of weeks ago. It was so comfy I almost fell asleep. What’s the big deal?
That explanation was certainly more info than I cared to know. Parts move around. I get it.
I was more worried about whether or not I had multiple sclerosis than the noise. My MRI tech was wonderful too, she explained how NOT enclosed I was, eliminating that possible claustrophobic feeling that may have popped up.
What did you have it for? Did you get to look at the results? I had an MRI a few years ago and I almost fell asleep in it. It was no more closed than a CT scanner, and the noise sounded like something out of a science fiction novel, so I was comfortable. Of course, I grew up around hospitals (both my parents are doctors) and I’ve worked in a hospital for 24 years and I’m nosy and like to watch procedures, so I’d seen them done before and watched the screen as they were done. Pretty dang cool!
Mishele, I’m still having excruciating pain in my neck and shoulder. Medication isn’t helping much at all. I didn’t get to look at the results. Maybe I will Monday when I talk with my doctor.
I found my MRI quite relaxing but it was done on my knee so I wasn’t fully inside it…plus they gave me earphones and I listened to U2. Was actually a pleasant way to spend a half hour.
I hope they find out what’s going on with you and get you on the fast track to recovery. Chronic pain is so wearing on a person….hang in there.
I never understood why after insisting that you have absolutely no metal on you for the procedure, that they then hand you a set of earphones. (Not that I’d be one to ever rip apart earphones… but) I’m thinkin’ that there’s metal and magnets in the headset!??
Jonco, I do hope they find what’s wrong and are able to adjust/repair it. My MRI was a lead in to 6 months of PT (Physical therapy.. a.k.a. pain & torture). It was a hassle, but in the end it was worth it. Hang in there and keep us posted.
I’ve had about 8 MRI’s one of the head and the rest on the back. I find it to be relaxing. When they put the headphones on to any radio stations I am at ease. Plus the nice cool room with a warm blanket, I could stay in there for hours.
I had a couple of MRIs about 5 years ago for trigeminal neuralgia. MRIs must also be time machines. The first time, I thought I was in there for about 20 minutes. My wife said it was over an hour.
Now if you want to talk pain, TN has to be among the worst. I suffered day and night for 4 years and visited about 15 or 16 different doctors, dentists, etc. including a neurologist with misdiagnosis after misdiagnosis and was prescribed numerous useless drugs until I found a neurosurgeon that knew exactly what I had. I actually had another neurosurgeon in Columbia, MO do the surgery, and instantly became 100% pain-free when I woke up.
It amazes me that while seeing so many medical ‘professionals’, practically none got the diagnosis right or could even suggest who I should go to. Then there’s the insurance issue, where they refused to cover the surgery… don’t get me started on that one.
Five years after the surgery, it’s all worth it especially when my kids laugh hysterically when their metal detector goes off when I hold it on my head.
dont they have open MRI’s now
I wasn’t terribly uncomfortable. I’m not claustrophobic so that wasn’t a problem for me. I can just imagine a child in there being scared to death. I didn’t get headphones but ear plugs and they put some pads next to my head so it pretty much softened the noise. I actually found it relaxing, except when you know you can’t move that’s when your nose starts to itch and things like that. Also, after laying perfectly still for those 23 minutes, I was in excruciating pain for the next hour.
I just wonder why, in this high tech age, that they can’t figure out a way to lessen if not completely mute the noise.
Yeah infidel, they have open MRIs, and I believe (correct me if I’m wrong) they’re also a lot quieter. Moochiecat and Ana probably had them in one of those, hence the calmness and openness they talk about.
And Julie, they can allow the headphones because then, they know exactly where the metal is. If you have a necklace or keys or some other metal, they don’t know exactly where they are, and even if they do, it may cover up key portions of your body, so they remove all OTHER metal from your body, then just ignore where the headphones are in the scan results.
It has nothing to do with where the metal is. An MRI is basically a giant magnet, bringing anything metal into it can cause some serious damage.
Nah Maoman, I’m just not claustrophobic and the sounds were cool.
I’m pretty sure the headphones they give are made of plastic.
After my MRI I ran right home to find out what all the noise was about. And here I am!
Mine was for my neck and was only 25 min. Only 25 minutes….I nearly freaked once or twice but I quickly put it down. I never opened my eyes for fear that I would lose it; so I pulled from lots of memories and revisited times past. When the tech said that this will be the last five minutes I was relieved. I don’t believe I could have spent much longer in there. Once I thought it was getting warm, but then I felt cool air on my face and that was calming!
First thing I said to the tech was that I thought it would be quiet. He said the CAT Scan is quiet, but the MRI is the noisy one. Hope never to have either of them ever again!
In the end, it’s all about “mind over matter”. Good luck to anyone who has not had one yet. It really isn’t that bad.
Few things to clarify…..
1) Headphones used in MRI do contain metal, but not all metal is ferromagnetic (meaning it will be sucked in). SOme of these metals include copper, nickel, aluminum, brass and titanium.
2) It is impossible to eliminate that LOUD noise, because it is actually the loud noise itself that helps create the image. We need a radio-frequency (sound wave) to stimulate your nuclei, so we give a real big one to do the job. As MRI’s get stronger, so will the sound needed to stimulate them.