Redngold From United States of America, joined Mar 2000, 6907 posts, RR: 51 Posted (8 years 8 months 3 weeks 16 hours ago) and read 1106 times:
...it happens to me.
That's what it feels like sometimes in my life. Friday was just another example.
I went in for an MRI (previously discussed) and went through the whole checklist of metallic items that needed to be removed and/or reported. I don't have any metal implants (yet) so I was pretty sure that by stripping naked everything would be fine. Put on the hospital gowns, got up in the MRI, started the procedure.
I asked for more air flow immediately, which the attendant did quite nicely. I wasn't sure I'd be able to stay still, so I tried to just "disappear" which I usually do in the dentist's chair. It worked. She calibrated the machine with no problem, then started the first scan. (Which sounded like a low-pitched alarm.)
No problem, except my elbows started feeling a little warm. Oh, I figured that was just the machine warming up, so when the scan was over I repositioned my arms so that I could feel more of the inside. It felt a little warmer during the second scan, but not terribly uncomfortable. (The second one sounded like a jackhammer.)
So for the third scan I folded my arms across my chest again. (This one sounded like a machine gun.) My elbows were the only place in contact with the inside. As the scan progressed, I felt them getting hotter and hotter, which I thought must just be in my mind. I tried to move my arms a little without moving my neck, but I couldn't. I kept thinking, "this isn't happening, I'm just getting uncomfortable from having to stay still" but I started to feel like my elbows were burning, especially on the right side. I don't know how long I waited, but I just couldn't believe it was happening.
Finally I couldn't stand it any more so I shouted and waved my arms. Fuck the scan, my elbow hurts!
So they stopped and pulled me out of the scanner, and my elbows were bright red. I had a palm-sized mark on my right elbow and smaller mark on my left side. I was scared, and even as a grownup woman I admit I was crying. What the hell just happened? The nurse who had set me up for the exam asked me if I had metal in my elbows, and I of course said, "Hell no, I would have told you!" She kept feeling my arms and I kept saying, "it's not just in my head, right? Can you feel it?" and she wouldn't answer, but finally they brought a doctor in to look at me and she (the doctor) confirmed that they could feel the burns.
I had been told I would need three full scans followed by three scans with injected dye, and I said I wanted to finish the scans as long as they promised me they would do something to keep me from getting burned any more. There was apparently some confused discussion and finally they decided they had gotten enough of the third scan, and the attendant had misread the order so I didn't need to have the dye series. I could go home.
Well, the nurse asked me to sit in the waiting area for 1/2 hour and then she would look at my elbows again. After that time, my right elbow had a mark roughly the size and shape of a regular band-aid and my left elbow was fine. So I went home, upset, but at least I don't have to go back.
This is why, even though I want to be a good patient and I am intrigued by medicine, I hate going in for even the most simple tests. If shit can happen to anyone, it happens to me. The radiologist doctor said she'd never had that happen to anyone before. She thinks it was because the contact point of my elbow against the machine caused a hot spot that concentrated the magnetic energy. I told her I wanted her to check the machine before she used it on any other patients. I also told her I wanted it put in my record that this had happened despite the fact I had no metal on me.
777236ER From , joined Dec 1969, posts, RR: Reply 1, posted (8 years 8 months 3 weeks 16 hours ago) and read 1086 times:
The actual magnetic field doesn't make you warm at all. The current in the gradient magnets (which also makes the hammering noise) can cause the machine to heat up. Your elbows were probably held on the sides, and during the scan got warm from the sides of the MIR.
Redngold From United States of America, joined Mar 2000, 6907 posts, RR: 51 Reply 2, posted (8 years 8 months 3 weeks 15 hours ago) and read 1065 times:
Uhh... yeah, I knew my elbows were against the sides. The rest of the surface didn't warm up, though. I'm just repeating what the doctor told me, that the contact had caused a hot spot to develop. My point is, this is not supposed to happen if you don't have metal on you.
777236ER From , joined Dec 1969, posts, RR: Reply 3, posted (8 years 8 months 3 weeks 15 hours ago) and read 1059 times:
The magnetic field doesn't cause the metal to heat up, it simply pulls at the metal object - which isn't a great thing if it's a pacemaker or clamp. The surface didn't warm up because the wire of the superconducting magnet is in liquid helium.
I don't know what it was. Clearly it wasn't the magnetic field because they got two good scans. Maybe it was psychological?
Redngold From United States of America, joined Mar 2000, 6907 posts, RR: 51 Reply 4, posted (8 years 8 months 3 weeks 15 hours ago) and read 1048 times:
OK if you read my story then you see that there's a red mark on my arm, plus the nurse and doctor both said they could feel the heat coming off my elbows. The thing was, I waited too long to tell them to prevent the burn. I thought it was in my head, but it wasn't.
EGGD From United Kingdom, joined Feb 2001, 12426 posts, RR: 40 Reply 5, posted (8 years 8 months 3 weeks 15 hours ago) and read 1039 times:
Thats odd.. I would've thought, being a devout Christian that you would be immune to this sort of thing...
Just kidding! I can honestly say I have no experience with this sort of thing, and I don't really know how MRI scans work, but my brother has had quite a few and he's never experienced this sort of thing. I'm guessing having your arms touching the sides had something to do with it though. Electrical Current passing through you when you touched either side? I'm sure that would explain why anything metal would heat up as well.. Maybe.
777236ER From , joined Dec 1969, posts, RR: Reply 6, posted (8 years 8 months 3 weeks 15 hours ago) and read 1038 times:
That's different, the patch isn't magnetic. The RF can cause a current in the metal in the patch, which heats up causing a burn.
You're told to take all metal off because you'll be in a MASSIVE megnetic field, in the order of 5000-20000 gauss - the planet 'only' has a 0.5 gauss field. It'll make any magnetic metal object a really dangerous projectile. I think a small boy was killed once when a metal object hit his head while he was in an MRI. Perhaps there was a concentation of RF pulses near your elbows, which somehow heated up the tissue. What part of the body was being scanned, if you don't mind me asking?
777236ER From , joined Dec 1969, posts, RR: Reply 8, posted (8 years 8 months 3 weeks 14 hours ago) and read 1005 times:
Well, different scans use different equipment, but when you're laid down your elbows are in plane (roughly) with your cervical spine, so I can't see why there'd be a concentration of RF pulses - especially ones that would be so localised. A mystery!
Talk to your doctor about it, see what he or she says. I hope this doesn't put you off nMRI scans though - they're absolutely amazing in my opinion.
Redngold From United States of America, joined Mar 2000, 6907 posts, RR: 51 Reply 9, posted (8 years 8 months 3 weeks 14 hours ago) and read 995 times:
I won't be put off to doing the scans again (I was willing to continue with the series as ordered) but the suggestion was made that I ask for padding for my elbows next time, to diffuse any possible heat and prevent any conduction.
Also, I'm really not that big. I am overweight, but more than 100 lbs. less than the highest allowable weight for that particular scanner. The reason I put my arms and elbows in that position was because 1) I felt most comfortable and most likely to be able to remain still that way, and 2) there was no reason to suspect it would cause a problem. But I'll sure as hell remember next time.
Redngold From United States of America, joined Mar 2000, 6907 posts, RR: 51 Reply 10, posted (8 years 8 months 2 weeks 5 days 12 hours ago) and read 904 times:
Found out, after doing some research, that this *is* a known problem, and that the tech should have told me to keep my body from touching the bore of the magnet. Not only that, but by having my elbows out to the side and hands on my chest, I formed "loops" with my own body tissue, which can also create inductive current. So my elbows were the ground for this, and were burned.
Maybe I'll forward the article to the radiologist who told me she'd never heard of this happening before.
777236ER From , joined Dec 1969, posts, RR: Reply 11, posted (8 years 8 months 2 weeks 5 days 12 hours ago) and read 899 times:
I formed "loops" with my own body tissue, which can also create inductive current. So my elbows were the ground for this, and were burned.
Loops are a big problem when patients are given an MRI with monitors like EKGs. The wires can loop around, and a current can be induced, making them very hot and burning patients, sometimes severly. I wouldn't have though a strong enough current could be induced in you to cause any problems though. The coils of the magnet are cooled so they super conduct. Maybe you got frostbite - if you elbows were there for an extended period you might not have noticed the cold.