9 ms·

I’ve always wanted to have an MRI. I want to know how it feels to have all of my protons reoriented by a giant magnet. Would I be the same person after?

kelseyfrog 3y ago
I've had a couple. Proton alignment is an imperceptible state. You're experiencing more significant neurological changes reading this message than having your protons reoriented.
- robopsychology 3y ago
  My wife works on MRI sequencing and has pretty long (> 1 hour) MRI scans quite often (2/3 times a week) as they all test each others research on themselves. She mentioned there are some scans where you actually do feel them and it's quite uncomfortable.
jjtheblunt 3y ago
The only thing you feel is heated a bit in my experience (sports injuries, torso and sinuses). However if they use contrast it might have lasting effects. I only had that once and swear it made me feel dopey for weeks.
- scythe 3y ago
  If you had nanoparticle contrast (ferumoxytol) it very well could have stuck around for weeks. Gadolinium chelate contrast is supposed to wash out in a few days, though.
yalue 3y ago
Having to hold perfectly still (possibly in an uncomfortable pose) in a giant machine that's making loud, uncanny noises for 20+ minutes is indeed a very bizarre, meditative experience. It is interesting, but, in my opinion, you're probably going to be happier not having the health concerns that lead to getting an MRI in the first place!
- cj 3y ago
  I had a MRI in college as part of a psychology experiment. If you can get into one of those studies, it's a free way to get a picture of your brain! I think I may have skewed their results, though. MRI is a very meditative experience and I'm pretty sure I fell asleep for brief moments when I was (supposed to be) memorizing and recalling pictures and words they were showing me on a monitor as part of the university experiment.
  - nuancebydefault 3y ago
    Indeed it tends to be meditative, especially because you have nothing else to do then holding still and relax.
wincy 3y ago
The MRI didn’t feel like anything. It wasn’t until the neurologist showed me images of my brain with my eyeballs right there in the front that I felt like I was going to have a panic attack. I have no idea how regular people just laugh off stuff like that. Awful existential crisis level dread seeing my mental meat.
- 13of40 3y ago
  For anyone wanting to relive that experience, you should know that (in the US at least) you can go to the imaging department at the hospital and get all of that data on a CD, and there's some good free software to render it. I've got a 3D print of my head somewhere that I made from a CT scan.
  - ttoinou 3y ago
    Noo way? My CD only contains a bunch of jpeg from the slices. What file format did you get ?
  - celdon25 3y ago
    > some good free software to render it Not going to share the name of it? :)
    - echo_time 3y ago
      If the images are in DICOM format, which is common, then dcm2niix should be able to convert them https://github.com/rordenlab/dcm2niix https://github.com/rordenlab/dcm2niix I think it can handle a few other formats as well. Once they are .nii(.gz) files, then mricrogl (https://www.nitrc.org/projects/mricrogl https://www.nitrc.org/projects/mricrogl) should be able to render it - of course, for a brain scan - this would be your whole head. Brain extraction is performed by more specialized software, but that would get you started.
  - Workaccount2 3y ago
    I did this and then realized I have no way of using a CD.
sigmoid10 3y ago
>to have all of my protons reoriented by a giant magnet Only a tiny percentage of protons will actually get excited by a typical MRI. Like one in a million.
- echo_time 3y ago
  This is incorrect - all of the protons align along the static (the strong 1.5, 3 , 9.4 etc Tesla) field, some point one way, and some the other - but they have all shifted so that they line up. The excite portion is a separate step, distinct from the static (B0) field. edit: distinct in some ways - the strength of the static field determines the RF used to flip the protons out of alignment.
  - sigmoid10 3y ago
    You are mixing up a few things here, but they are all missing the point. At normal body temperatures, their thermal energy distribution prevents most protons in a human from aligning parallel or antiparallel with the static field, even at MRI field level strengths of several Tesla. The excitation by the varying field, which only affects another one-in-a-million of those aligend protons, is indeed another step, meaning that even fewer protons actually get to experience the precession effect. So about one in a million protons gets aligned with the static field and less than one in a trillion gets to produce a measurable signal. But since there are so many of them, (~10^20 per mm^3 for water), you still get enough (about 1000 protons or so per voxel) to measure a signal at 2 Tesla. With higher field strengths you can get a bit more and thus more resolution but even at 10 Tesla you won't align all of your protons - not even close.
oh_sigh 3y ago
I've had a few. There is definitely a weird feeling I get inside of them at specific certain points in the process, but I don't know if it is from the magnetic field, or if it is from some really high pitch vibrations/sounds that come off the machine.
RobotToaster 3y ago
I found it oddly relaxing and fell asleep.
nuancebydefault 3y ago
In the hospital where I went a few times, they show a relaxing video while the MRI is taken. You look at a projection via a tilted mirror close to your eyes. Once it was featuring pandas, it is really nice to experience the panda effect inside the machine. I've never been anxious about the scan.
gnarcoregrizz 3y ago
I've felt a bit of heat from the radio waves, especially during the fMRI sequence. Personally, I get a bit claustrophobic during brain MRIs because of the restricting face coils, and you have to go pretty deep into the tube. No idea why people get weirded out by seeing pictures of their brain. I've never felt that. I think its cool.
jlokier 3y ago
Your protons are also oriented by the Earth's magnetic field, and the magnets in your phone speakers. Larmor precession (the effect) occurs in low fields just as in high fields. The energy state differences from Earth's field are generally too small to be useful for MRI with enough quality in a reasonable time, but low-field MRI is a research area. I actually felt a strong sensation when I had a high resolution brain MRI for research, and I rather enjoyed it. It switched on and off a few times during the scan, and it felt a bit like having a back massage, or significant mechanical vibrations in my back, or that feeling like gentle electric currents during some therapies, except for switching on and off abruptly. I asked about this after the scan because I had been told you don't feel anything. Surely it wasn't just my imagination, from the noises? Was it from machine vibrations? I didn't have any metal in my body except amalgam fillings, and they said those wouldn't affect it. And, if I could feel something, perhaps it wasn't as harmless as they made out. They explained after, some people feel a stimulation of their peripheral nervous system when the RF is on, from the tens of kW of microwave energy beamed through the body. For a few people this sensation is too much, even painful, and they have to stop which is one reason for the patient having the mechanical alert button. But most people don't feel anything at all from the MRI, just psychological feelings associated with the strange noises and confinemnt. They said it's a peripheral nerve stimulation sensation, a kind of phantom feeling, rather than a physical effect on the body being sensed by the nerves. Don't ask me why I felt it in my back given it was a head and neck scan. I enjoyed how it felt when I didn't know what it was, as it felt like it might loosen up my back a bit. I was a bit disappointed to not feel anything the next time I had a head MRI, for a medical reason (thankfully nothing found). The research scan had twice the field strength of the medical scan, and presumably different RF settings. Perhaps that made the difference.
- scythe 3y ago
  >low-field MRI is a research area. Not just a research area! Recently on the DXMP mailing list someone was asking about QA procedures for their 0.064 tesla scanner. You can buy permanent magnets that strong without much trouble. I was very surprised since I wasn't aware they were in production — even searching Web results for "low-field MRI" in due diligence for this comment, I still only find papers and projections. Nonetheless, the Hyperfine Swoop exists, and you can buy it today: https://hyperfine.io/ https://hyperfine.io/
tonymillion 3y ago
You can’t feel it, and you have to stay still for a long time sometimes in uncomfortable positions. All the while trying not to laugh at the funny noises the machine makes which will blur the image and make the procedure even longer. It really does sound like the machine is farting sometimes…
worldsavior 3y ago
This is the most stupidest comment I ever seen. No, it's not fun to be at a hospital. No, you shouldn't want to be at a hospital. And yes, it's a bit masochist.

kelseyfrog 3y ago

I've had a couple. Proton alignment is an imperceptible state. You're experiencing more significant neurological changes reading this message than having your protons reoriented.

robopsychology 3y ago
My wife works on MRI sequencing and has pretty long (> 1 hour) MRI scans quite often (2/3 times a week) as they all test each others research on themselves. She mentioned there are some scans where you actually do feel them and it's quite uncomfortable.

jjtheblunt 3y ago

The only thing you feel is heated a bit in my experience (sports injuries, torso and sinuses). However if they use contrast it might have lasting effects. I only had that once and swear it made me feel dopey for weeks.

scythe 3y ago
If you had nanoparticle contrast (ferumoxytol) it very well could have stuck around for weeks. Gadolinium chelate contrast is supposed to wash out in a few days, though.

yalue 3y ago

Having to hold perfectly still (possibly in an uncomfortable pose) in a giant machine that's making loud, uncanny noises for 20+ minutes is indeed a very bizarre, meditative experience. It is interesting, but, in my opinion, you're probably going to be happier not having the health concerns that lead to getting an MRI in the first place!

cj 3y ago
I had a MRI in college as part of a psychology experiment. If you can get into one of those studies, it's a free way to get a picture of your brain! I think I may have skewed their results, though. MRI is a very meditative experience and I'm pretty sure I fell asleep for brief moments when I was (supposed to be) memorizing and recalling pictures and words they were showing me on a monitor as part of the university experiment.
- nuancebydefault 3y ago
  Indeed it tends to be meditative, especially because you have nothing else to do then holding still and relax.

wincy 3y ago

The MRI didn’t feel like anything. It wasn’t until the neurologist showed me images of my brain with my eyeballs right there in the front that I felt like I was going to have a panic attack. I have no idea how regular people just laugh off stuff like that. Awful existential crisis level dread seeing my mental meat.

13of40 3y ago
For anyone wanting to relive that experience, you should know that (in the US at least) you can go to the imaging department at the hospital and get all of that data on a CD, and there's some good free software to render it. I've got a 3D print of my head somewhere that I made from a CT scan.
- ttoinou 3y ago
  Noo way? My CD only contains a bunch of jpeg from the slices. What file format did you get ?
- celdon25 3y ago
  > some good free software to render it Not going to share the name of it? :)
  - echo_time 3y ago
    If the images are in DICOM format, which is common, then dcm2niix should be able to convert them https://github.com/rordenlab/dcm2niix https://github.com/rordenlab/dcm2niix I think it can handle a few other formats as well. Once they are .nii(.gz) files, then mricrogl (https://www.nitrc.org/projects/mricrogl https://www.nitrc.org/projects/mricrogl) should be able to render it - of course, for a brain scan - this would be your whole head. Brain extraction is performed by more specialized software, but that would get you started.
- Workaccount2 3y ago
  I did this and then realized I have no way of using a CD.

sigmoid10 3y ago

>to have all of my protons reoriented by a giant magnet Only a tiny percentage of protons will actually get excited by a typical MRI. Like one in a million.

echo_time 3y ago
This is incorrect - all of the protons align along the static (the strong 1.5, 3 , 9.4 etc Tesla) field, some point one way, and some the other - but they have all shifted so that they line up. The excite portion is a separate step, distinct from the static (B0) field. edit: distinct in some ways - the strength of the static field determines the RF used to flip the protons out of alignment.
- sigmoid10 3y ago
  You are mixing up a few things here, but they are all missing the point. At normal body temperatures, their thermal energy distribution prevents most protons in a human from aligning parallel or antiparallel with the static field, even at MRI field level strengths of several Tesla. The excitation by the varying field, which only affects another one-in-a-million of those aligend protons, is indeed another step, meaning that even fewer protons actually get to experience the precession effect. So about one in a million protons gets aligned with the static field and less than one in a trillion gets to produce a measurable signal. But since there are so many of them, (~10^20 per mm^3 for water), you still get enough (about 1000 protons or so per voxel) to measure a signal at 2 Tesla. With higher field strengths you can get a bit more and thus more resolution but even at 10 Tesla you won't align all of your protons - not even close.

oh_sigh 3y ago

I've had a few. There is definitely a weird feeling I get inside of them at specific certain points in the process, but I don't know if it is from the magnetic field, or if it is from some really high pitch vibrations/sounds that come off the machine.

RobotToaster 3y ago

I found it oddly relaxing and fell asleep.

nuancebydefault 3y ago

In the hospital where I went a few times, they show a relaxing video while the MRI is taken. You look at a projection via a tilted mirror close to your eyes. Once it was featuring pandas, it is really nice to experience the panda effect inside the machine. I've never been anxious about the scan.

gnarcoregrizz 3y ago

I've felt a bit of heat from the radio waves, especially during the fMRI sequence. Personally, I get a bit claustrophobic during brain MRIs because of the restricting face coils, and you have to go pretty deep into the tube. No idea why people get weirded out by seeing pictures of their brain. I've never felt that. I think its cool.

jlokier 3y ago

Your protons are also oriented by the Earth's magnetic field, and the magnets in your phone speakers. Larmor precession (the effect) occurs in low fields just as in high fields. The energy state differences from Earth's field are generally too small to be useful for MRI with enough quality in a reasonable time, but low-field MRI is a research area. I actually felt a strong sensation when I had a high resolution brain MRI for research, and I rather enjoyed it. It switched on and off a few times during the scan, and it felt a bit like having a back massage, or significant mechanical vibrations in my back, or that feeling like gentle electric currents during some therapies, except for switching on and off abruptly. I asked about this after the scan because I had been told you don't feel anything. Surely it wasn't just my imagination, from the noises? Was it from machine vibrations? I didn't have any metal in my body except amalgam fillings, and they said those wouldn't affect it. And, if I could feel something, perhaps it wasn't as harmless as they made out. They explained after, some people feel a stimulation of their peripheral nervous system when the RF is on, from the tens of kW of microwave energy beamed through the body. For a few people this sensation is too much, even painful, and they have to stop which is one reason for the patient having the mechanical alert button. But most people don't feel anything at all from the MRI, just psychological feelings associated with the strange noises and confinemnt. They said it's a peripheral nerve stimulation sensation, a kind of phantom feeling, rather than a physical effect on the body being sensed by the nerves. Don't ask me why I felt it in my back given it was a head and neck scan. I enjoyed how it felt when I didn't know what it was, as it felt like it might loosen up my back a bit. I was a bit disappointed to not feel anything the next time I had a head MRI, for a medical reason (thankfully nothing found). The research scan had twice the field strength of the medical scan, and presumably different RF settings. Perhaps that made the difference.

scythe 3y ago
>low-field MRI is a research area. Not just a research area! Recently on the DXMP mailing list someone was asking about QA procedures for their 0.064 tesla scanner. You can buy permanent magnets that strong without much trouble. I was very surprised since I wasn't aware they were in production — even searching Web results for "low-field MRI" in due diligence for this comment, I still only find papers and projections. Nonetheless, the Hyperfine Swoop exists, and you can buy it today: https://hyperfine.io/ https://hyperfine.io/

tonymillion 3y ago

You can’t feel it, and you have to stay still for a long time sometimes in uncomfortable positions. All the while trying not to laugh at the funny noises the machine makes which will blur the image and make the procedure even longer. It really does sound like the machine is farting sometimes…

worldsavior 3y ago

This is the most stupidest comment I ever seen. No, it's not fun to be at a hospital. No, you shouldn't want to be at a hospital. And yes, it's a bit masochist.