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My father died of a heart attack on the floor of an oil rig in 1972 6 weeks before his 48th birthday. I am the oldest of 6 and still had 3 siblings in HS at the time. Now in my mid-70s, I am grateful that when I wake up with arthritic pain, I am still alive.Originally Posted by Jim Koepke
Ken
So much to learn, so little time.....
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I had an MRI just ,maybe two weeks ago. They were looking for bad stuff ! Why can’t people be more upbeat ? I’m old and
getting some kind of vertigo. But I would rather crawl than use a walker ! But a big go-cart would be OK.
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My dad died at age 63 from a stroke, his dad passed at 48 from a brain tumor I will be 81 this July… thank you Lord!
Yes I have had many MRIs.
Retired Guy- Central Iowa.HVAC/R , Cloudray Galvo Fiber , -Windows 10
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Michael, the sounds you hear are normally caused by the gradient coils changing the main magnetic field in a precise way.
Have you ever seen a child build something with a set of blocks? Imagine your body built out of a child's blocks. Now we'll call those individual blocks voxels. An MRI image is made by the machine causing each voxel to produce its own distinct, individual RF signal. The machine knows in 3-D from where a given RF signal with a specific frequency was produced. The human body is made up primarily water, H2O. The MRI image is made by studying the hydrogen molecules in the body.
Different pulse sequences will produce dramatically different gradient pulses/fields and thus dramatically different sounds.
Last edited by Ken Fitzgerald; 04-19-2024 at 8:54 PM.
Ken
So much to learn, so little time.....
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My father also died too soon, but he smoked and didn't really take care of his health. I've survived long past his death age.
Mike
[Incidently, very good thread. I've learned a lot about an MRI.]
Last edited by Mike Henderson; 04-20-2024 at 11:14 AM.
Go into the world and do well. But more importantly, go into the world and do good.
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My mother had 4 older brothers. They all died fairly young - unfiltered Camels all day long. She lived to be 92.
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Fascinating Ken, I had no idea and curiosity made me ask AI. This was the reply and reads like science fiction, at least to me. There are some real smart folks in this world.
“MRI, or Magnetic Resonance Imaging, utilizes powerful magnets and radio waves to generate detailed images of the body's internal structures. Here's how it works:
- Alignment of Hydrogen Atoms: The patient lies within a strong magnetic field, which aligns the hydrogen atoms in their body along the magnetic field lines.
- Radiofrequency Pulse: A radiofrequency pulse is then applied, causing the aligned hydrogen atoms to absorb energy and temporarily deviate from their aligned positions.
- Relaxation: When the radiofrequency pulse is turned off, the hydrogen atoms gradually return to their aligned positions, releasing energy in the form of radio waves.
- Signal Detection: Specialized coils detect these emitted radio waves.
- Image Reconstruction: A computer processes the signals to construct detailed images of the internal structures based on the behavior of the hydrogen atoms in different tissues. “
My three favorite things are the Oxford comma, irony and missed opportunities
The problem with humanity is: we have paleolithic emotions; medieval institutions; and God-like technology. Edward O. Wilson
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Michael, AI gave you the truth!
The body tissues are made up with a large amount of water (H2O). All atoms have electrons spinning around the nucleus and thus their own resultant electromagnetic field which has north and south poles. In normal living conditions those magnetic fields are unaligned and point in different directions. The main magnetic field in an MR magnet has a north and south pole. When a body is placed into it the fields of the hydrogen atoms electromagnetic field align with the main magnets field. Now imagine the electromagnetic field of each atom as a folded umbrella with a painted spot on the edge in one place, spinning on its pointed top. When the RF pulses and gradient magnetic pulses are applied to it, each umbrella (hydrogen atom) gains energy, unfolds, and those spots become synchronized. When the RF pulse is removed, the umbrella begins to fold, and spots try to become once again unsynchronized. Thus, the hydrogen atoms give off very small RF signals. The rate of the folding of the umbrella (atoms electromagnetic fields realigning with the main MRI magnets field) and the return to the spots becoming unsynchronized is dependent on the amount of hydrogen and the purity of neighboring elements around those atoms. Thus, each atom gives off 2 distinct signals which have their own time relationship with respect to the RF pulse being removed.
Remember I mentioned volume units or voxels (the kids building blocks)? Each voxel will have its own specific individual frequency bandwidth. When the MR RF receiver gets the signal given off by the atoms, the computer by analyzing the frequency of the received signal, knows where to place that signal within the scanned body.
This results in what is called T1 and T2 RF signals. These different times result in different series of scans each of which have their own particular use as they try to image a particular disease or physical abnormality.
In some ways it's really complex and in other ways it's pretty basic. Basically the MR image is made from performing an analysis of the amount of hydrogen atoms within areas of the body. It has its uses and other modalities like CT, x-ray, ultrasound and nuclear medicine have their uses.
Last edited by Ken Fitzgerald; 04-21-2024 at 4:34 PM.
Ken
So much to learn, so little time.....
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I believe the concern is with ferrous metals/alloys. Mercury is not a ferrous metal.
Interesting history of tooth fillings.... https://www.elmsleighhouse.co.uk/blo...ental-fillings
Last edited by Patty Hann; 04-21-2024 at 2:52 AM.
"What you see and what you hear depends a great deal on where you are standing.
It also depends on what sort of person you are.”
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No one on either side of my family has ever made it to 80. I'm currently the oldest, and the number of candles required on the cake each year is making it really hard to stay optimistic.
Chronic TMB is a pretty relentless disease.
Yoga class makes me feel like a total stud, mostly because I'm about as flexible as a 2x4.
"Design"? Possibly. "Intelligent"? Sure doesn't look like it from this angle.
We used to be hunter gatherers. Now we're shopper borrowers.
The three most important words in the English language: "Front Towards Enemy".
The world makes a lot more sense when you remember that Butthead was the smart one.
You can never be too rich, too thin, or have too much ammo.
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I dont think they want me dead just to suffer.
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Very informative Ken. Unfortunately when I had an MRI a couple years ago when I was going through prostate cancer I didn't get asked anything about metal working. No problems so I guess I didn't have any fragments. My question is if titanium implants cause any problems? Nowadays most orthopedic hardware I'm familiar with is titanium rather than stainless steel.
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If Titanium were a problem I'd have been plastered to the Simon Med 3T magnet a long time ago.
I have Titanium in my back and neck.
Titanium is a non-ferrous metal.... a magnetic field will have no effect on it.
"What you see and what you hear depends a great deal on where you are standing.
It also depends on what sort of person you are.”
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think its called an Orbit what they do for your eyes. have been in the tube a few times
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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.
Last edited by Ken Fitzgerald; 04-22-2024 at 8:06 PM.
Ken
So much to learn, so little time.....
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