MRI Question

[Patty Hann]

Titanium is a non-ferrous metal so the magnet's magnetic field itself won't have any affect on it. The MRI RF pulses used to give energy to the hydrogen atoms could potentially warm the titanium a very little bit but I doubt it would be noticeable but could potentially affect the image quality due the RF absorption in that given area. Don Orr would be more informed about that aspect of it.

Would you believe that some tattoos due to the metals in the inks can affect image quality on an MRI image?

Some of the most difficult image quality problems to troubleshoot, have been caused by some of the strangest things. For example, I was sent to work on a mobile MRI that was having intermittent image quality problems. The cause? Turned out in the scan room, there were several burned out incandescent light bulbs that were burned out. Removing the burned out bulbs from the scan room fixed the problem. It would appear that the broken filaments in the bulb were being flexed and touching during a scan very intermittently and the resulting arc/spark caused a very small RF signal to be generated, producing an "artifact" in the images. In fact, that is how I found the cause. During a scan I happened to notice a very momentary flash of light from what was a burned out bulb. I removed the bulbs, probems resolved.

Tattoos include "permanent eye liner". I don't think they will do an MRI on a person's head if he/she has permanent eye liner.

[Mike Henderson]

Tattoos include "permanent eye liner". I don't think they will do an MRI on a person's head if he/she has permanent eye liner.

Here's some information about that - https://pubmed.ncbi.nlm.nih.gov/11836774/

Mike

[Patty Hann]

Here's some information about that - https://pubmed.ncbi.nlm.nih.gov/11836774/

Mike

Good info to have (not that I have any tattoos).
A few years ago I asked the tech what would happen if I had permanent eyeliner and needed an MRI on my brain.
He said they wouldn't normally do it unless I signed off pages of liability related paperwork

[Don Orr]

Wow, this an old thread that popped up again. I've been retired for over 5 years now but the basic technology hasn't changed much. I was an MRI Technologist for 25 years for a local Medical Center. Both Ken and AI are correct. Ken is an actual expert in how the machines work and has provided some fantastic real-life information. Where I worked we were not very concerned about tattoos unless they were very colorful and fairly fresh, even eyeliner. Some of the inks used for tattoos can contain metallic pigments and that is the issue. Glitter in makeup is more of a real issue and we would have them wash it off. As you know not many metals are magnetic. If they are they can be "deflected" out of their resting position and could cause a problem. Think of a steel fragment in your eye being torn out by a very powerful magnet. It actually happened in the early days of MRI and is documented in the safety literature. It's why we had to take X-rays of peoples heads if they checked "yes" to metal of any kind in their eyes on the safety questionnaire. As tattoos age the pigments break down and are removed from the body naturally. That's why colorful tattoos don't stay colorful. The biggest safety issue with metal in MRI is heating. Very few surgical implants are magnetic these days. They even have MRI safe Pacemakers now. Implanted metals absorb the RF energy and is deposited as heat, even to the extent of causing burns. The other issue is image quality. Any metal will cause severe distortion of the acquired images. It's called a "magnetic susceptibility artifact" and is harmless to the patient-except for limiting the diagnostic capabilities of the image. You should see what dental braces do to a brain/face image !

Overall MRI is an incredible diagnostic tool that uses no ionizing(harmful) radiation to produce amazing images. Some of the newer techniques are also incredibly fast. Yes, it's noisy and boring but the results can save lives, or at least tell how bad your knee really is. Nothing to be afraid of as long as you are properly screened by staff. If you suffer from claustrophobia the newer Open MRI's are much better than back in the early days.

Hope this helps.

[Ken Fitzgerald]

The helium pump or the operation?

George, I'd forgotten about the coldhead noise a patient hears. The MRI magnet is a supercooled (LHe = liquid helium), superconductive, electromagnet. Once it's ramped up to field strength, there is no power supply connected to it to keep the electromagnetic field going. LHe is very expensive and in short supply. The MRI magnets coils are inside a cryostat (vacuum bottle if you will). That cryostat is inside a 2nd cryostat. The inner cryostat contains LHe which cools the magnet's coils. The outer cryostat is cooled to slowdown the boiloff of the LHe within the inner cryostat. Think of it as a donut inside a donut. The outer cryostat is cooled by chilled compressed helium gas. The coldhead (compressor) for the gas is attached to the magnet and runs 24x7 to cool the magnet and maintain its magnetic field. When a patient is in the bore of the magnet, they can hear the pumping sound of the compressor as it cools the outer cryostat.

[Ken Fitzgerald]

Ken is an actual expert in how the machines work and has provided some fantastic real-life information.

Thank you but hardly!

[Ronald Blue]

A few days late on replying here. I had an MRI on my shoulder in 2021. After two tries. Because welding was a regular part of my occupation they X-rayed my head to make sure no artifacts were present in my eyes. As for the two tries....a magic pill was given for the second time. Something about being inside a tube with little room wasn't calming to me. I will know if I ever need another one.

[Patty Hann]

A few days late on replying here. I had an MRI on my shoulder in 2021. After two tries. Because welding was a regular part of my occupation they X-rayed my head to make sure no artifacts were present in my eyes. As for the two tries....a magic pill was given for the second time. Something about being inside a tube with little room wasn't calming to me. I will know if I ever need another one.

Prior to one of my many MRI's (Neck, shoulder, lower back, hip, and knee, some multiple times over the years) I asked the tech which sex has more "claustrophobia" reactions to being in the tube.
His answer: men, by far. He didn't offer any explanation as to why.
Anther time, at another site (and so a different tech, this time a woman, I asked the same question.) Her answer: men, much more often than women, have a hard time with it.

[Ken Fitzgerald]

They can give a medication that helps relieve that. IIRC versed is the med.

[Alan Lightstone]

They can give a medication that helps relieve that. IIRC versed is the med.

If you have an IV in. Otherwise, taking any benzodiazepine tablet an hour before usually works.

I had LASIK done in Canada 28 years ago. Supposedly there were tiny metal fragments in one of my eyes. So before my first MRI they did a head X-ray, and determined no issue. And, having anesthetized many patients in MRI scanners, you really have to be even more OCD than usual regarding ferromagnetic equipment. Fortunately, over the years many monitoring devices that we need to safely anesthetize patients became available to use in MRI scanners. But it is a PIA. When I read news articles regarding bad mishaps (oxygen tanks, metal carts, etc...) I shake my head. Never, ever should have ever happened.

Really learned a ton from Ken's post. Thanks for that.