The forums were originally run on Vanilla and ran from January 2011 to July 2024. They are preserved here as a read-only archive. If you had an account on the forums and are in the archive and wish to have either your posts anonymized or removed entirely, email us and let us know.

While we are no longer running Vanilla, Patreon badges are still being awarded, and shoutout forum posts are being created, because this is done directly in the database via an automated task.

MRI experience

Hey y'all,
I had an MRI done today and wanted to share my experience. The MRI scan was of my knee and my magnet is in my left hand's pinky finger. We think it's an N42 based on my last post:

Anyway, the experience:

- I wrapped my finger in scotch tape pre-emptively (although pretty sure it did nothing)
- Magnet started flipping like crazy as I approached the machine (similar to MacBook Pro laptop speakers, hate those)
    - I'd estimate about 5 feet from the machine, it started flipping
- Talked to the tech about it, she said it was a 3T machine and suggested I could use a lower strength machine but I insisted on doing it
    - Machine was branded as a GE (didn't get a model number =/)
- Lied down in machine, held finger up on chest (it got close to but never entered machine, scan was only for knee)
    - They gave me a trigger to squeeze in case anything went wrong
- During the scans, the magnet didn't seem to vibrate/move at all
- Magnet flipped a bunch again as I got up and walked away from machine
- MRI scans look like they came out clear with no interference from the magnet (will be seeing the doctor next week)
- Magnet feels fine and reacting as per normal


Displaying all 8 comments
  1. So during the MRI scan the magnet was completely motionless? This looks peculiar. I wonder why, can anyone give an explanation?
  2. Yep, during the MRI scan the magnet felt like it didn't vibrate/move at all. I was curious about this too so I did a little more research. This slideshare breaks down the parts of an MRI machine:

    I'm guessing I felt the superconducting magnet as I approached but the coils (i.e. what make the images possible) generate fields that are contained within the machine (i.e. nowhere near my finger which was out of the machine)
  3. Another guess would be that the MRI's field is cycled at such a high frequency (in the tens of MHz if I got that correctly from light googling) that the oscillation cannot be felt, but I'm not sure if you could still pick that up with your nerves.
  4. @S0III0s, that theory is interesting. I used to play around with high voltages a lot. It was always fascinating how once you get to a certain frequency, you'll burn your flesh, but can't feel the slightest thing. Crazy how nerves work like that.

    Is it possible if the MRI slices were excited perpendicularly to the magnet it wouldn't cause it to vibrate or flip?
  6. @misslitty I suppose that's possible, I think... But the magnet would need to point in the exact same direction the entire time... And be perfectly lined up... right? >~<
  7. @misslitty I suppose that's possible, I think... But the magnet would need to point in the exact same direction the entire time... And be perfectly lined up... right? >~<
  8. @Zerbula Ooh that's a good point, doesn't seem likely that would be the case
Displaying all 8 comments