[dylan604]

What was your experience with the MRI like? Specifically, did you "feel" it? I've had my knee scanned for ACL damage, and have spoken to a few other acquaintances that have had scans as well. We've all discussed having some sensation in the exact part of the body being scanned. We all just happened to similar sports based knee injuries. It was just the slightest of tingling, but noticeable. Definitely not painful or anything scary. Was it just psychosomatic? Very possibly, but it's interesting that we all experienced it.

[riahi]

The RF pulses and field gradients can directly stimulate the peripheral nerves. I have had involuntary muscle twitching triggered by many pulse sequences. It’s not unheard of. It made me more sympathetic for patients who have motion in images. It could be that the particular combination of pulse sequence and their nerves don’t jive and triggers movement.

Source: Radiologist (and personal experience in the bore)

[lostlogin]

If the patient isn’t twitching occasionally, the resolution is too low. We aim to be just below peripheral nerve stimulation threshold.

I’m sort of joking, but if you aren’t ever getting PNS, the machine is not being run very hard.

However the sensation you get in the region being scanned feels more like heating than PNS to me. You notice it more on high SAR sequences, suggesting that might be the cause. PNS just feels like twitching you can’t control, but ones milage may vary as this is anecdotal.

Source: MR radiographer.

[riahi]

I don’t think it’s heating. I think it’s PNS because my leg will periodically twitch which I can time with the pulse sequence.

I also have some small ACL reconstruction hardware in the knee which might interact and predispose that leg to moving…

I am well acquainted with high SAR abdominal scans in a 3T from my time doing scan certification in a petmr. Even though I “know” that tissue heating from high SAR is a thing, it always surprises me when my abdomen gets warm.

[lostlogin]

I used a high spec Siemens Avanto which a University owned. We used to get people complaining about PNS in the left hip and just above the bridge of the nose. It was a weird thing, and mainly happened on cardiac scans. Some found it too painful to continue with scanning.

I’ve had a little bit of PNS, but nothing that strong.

The SAR sensation of being heated from the inside is an unusual one, I’m not sure I’ve had anything else do that?

[secretsatan]

I had a head one done, it was very noisy, but the thing I found most uncomfortable, or rather, disconcerting, is when they injected the tracing fluid.

I thought they would do it all the way through, but then I suddenly heard the pump start halfway through the procedure and a slightly cooler fluid running up inside my arms.

[zrail]

I have had an abdomen MRI. I definitely felt sensations when the machine was doing particular sets of scans.

Also, I accidentally left my wedding ring on (I informed them, they were not interested in the slightest). My right felt hot during the scans. Not painful burning hot, but warmer than body temp for sure.

[dylan604]

I guess forgetting your gold ring in an MRI lets you know it's not gold plating of a cheaper metal!

[tgv]

MRI can cause a tingling sensation. Apparently, it can be quite noticeable when you make a loop, e.g. with your arms. See peripheral nerve stimulation.

[dylan604]

make a loop? wouldn't that require breaking the cardinal rule of not moving during the scan?

[green-salt]

For my knee scans I could move into a position that was comfortable for me which actually I think was arms folded across my abdomen, but then you just do not move while the imaging is happening, which will have a distinct sound.