Getting an MRI?

[RJSakowski]

An iron sliver in the cornea will hurt like hell. I had one many years ago and an intern at the ER tried removing it with a hypodermic needle. He said he got it but the pain was still there. Out of desperation, I held a large horseshoe magnet close to my eyeball and pulled it out. Later, an ophthalmologist advised me to never use a magnet fear of twisting the sliver and hooking it doing further damage.

Foreign object are not likely to be as painful outside of the cornea. They may feel like a slight irritation which you become used to over time. Additionally, tissue can form over the object further diminishing the pain.

My advice, if you're going for an MRI and you've worked with steel/iron, get the x-ray.

 

[Karl_T]

How about your hands? i got enough metal slivers in them for a magnet to stick

 

[RJSakowski]

The MRI doesn't detect iron in the body. It detects hydrogen. It is an imaging device using nuclear magnetic resonance or NMR, discovered in the 1930's but not used for medical imaging until the late 1970's

MRI flips the spinning protons (hydrogen nucleus) an detects the resonant frequency when they flip back. The protons have slightly different frequencies depending on how they are chemically bound and the MRI uses that to distinguish between fat hydrogen, water hydrogen, etc. I5t is this ability to differentiate the different chemistries of the hydrogen containing molecules that make it so useful in diagnosing soft tissue issues.

Magnets used for MRI are usually superconducting electromagnets operating at field strengths of .5 to 8 tesla. A tesla is 10,000 gauss and the Earth's magnetic field is about .5 gauss in comparison. Rare earth magnets can generate field strengtnhs approaching that of the MRI magnet but on a much smaller scale. It is the combination of the high field strength and the large field size that makes the MRI elecromagnet so dangerous in the presence of ferrous metal.

Enough of the medical physics lecture. Let's get back to machining!

 

[JPigg55]

Sorry to hear about the injury Terry, what happened if you don't mind sharing ???
I've had multiple MRI's over the past 12 years due to my back. I've been surprised that they haven't asked about performing any metalworking before the last few, just asked if I had any metal implants.
I have remembered from them asking on the first few and have made sure not to do any work in my shop or elsewhere else a couple weeks before any MRI to allow my body time to rid itself of any chips/slivers. An X-ray has always been required prior to any of my MRI's as well, although they only X-ray the area in question and not the entire body.

 

[kvt]

Yea, They even delayed one of my MRIs one time because they didnt have any one to do the Eye check. but they have never done an xray prior. Prob 20 plus MRIs, they ask a bout metal, and get the Plate etc in the cervical spine, and staple in the shoulder. Last xray they said they could not find the staple in my shoulder, And a few back I remember an MRI tech asking if I had some metal in my knee as it was getting a funny reading like they get from metal. I think I know where it went then.
Hope your shoulder gets better and take care of it. Mil doc told me back in 80 that I needed shoulder worked on, He moved, and the next bunch just sent me to Pain and torture and a bottle of Motron. They did that for the next 20 years, THen finally when I could no longer pick up a phone they said well maybe we have a problem. WHen they did the MRI they said Oh this is going to hurt when we pump it full of fluid, They started and I said it felt better, They went Oh sh** we are in trouble.

 

[RJSakowski]

MRI tales:
https://www.jameco.com/Jameco/workshop/MyStory/Wayne-MRI-tales.html

 

[brino]

I hadn't seen that one Bob, but it reminded me of this one:
https://www.jameco.com/Jameco/workshop/MyStory/magnetic-fields-as-an-mri-tech-intern.html
-brino

 

[Terrywerm]

Long story short I fell inside a trailer at work about a month ago and wrenched my right arm up around and behind my head in the process. I reported the fall but figured I only pulled a muscle or something, so did not go to the doctor. After four weeks with little improvement I figured it was time to get it checked out. Luckily, there does not seem to be any damage to the muscles that make up the rotator cuff, but my doc thinks I tore one of the ligaments that attaches my biceps to my shoulder which will require surgery to repair it and get rid of the pain. I guess we'll know more next week.

 

[owl]

I had an MRI and they asked about my profession. Concerned, I told them that I was a hobby machinist. They, at that time, said they only worried about professional ones... it turned out OK, but it was a bit spooky.

 

[Bob Korves]

I had an MRI and they asked about my profession. Concerned, I told them that I was a hobby machinist. They, at that time, said they only worried about professional ones... it turned out OK, but it was a bit spooky.

Amateur chips in the eye cause no damage...