MRI Machines

[RFI-EMI-GUY]

Well I spent a half hour of my life under the magnet of an "open" MRI
machine yesterday. Still a bit claustrophobic. While I sort of
understand the theory of the MRI, what I don't understand is what
creates all the noise and racket. Any experts out there that can tell me
whats going on?


--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

 

[Joerg]

Well I spent a half hour of my life under the magnet of an "open" MRI
machine yesterday. Still a bit claustrophobic. While I sort of
understand the theory of the MRI, what I don't understand is what
creates all the noise and racket. Any experts out there that can tell me
whats going on?

It's coming off the gradient magnets, usually. I hope all is ok and you
won't receive any nasty diagnosis from the session.

 

[Joerg]

A few years ago they scanned my sinuses.

I must admit a claustrophobic feeling also :-(

That's probably because you guys don't have a house with a narrow crawl
space. At least you can be sure that there won't be critters such as
rattle snakes waiting inside that MRI tube.

 

[J.A. Legris]

Pulsed gradient coils. These are "small" 3-axis coils that sweep a
gradient field across your innards, modulating the nuclear resonant
frequencies of your molecules to produce the spatial resolution. These
are generally water-cooled, with ballpark 20 KW constant-current
drivers per axis, playing all sorts of weird waveforms.

They scanned my head last year, with the gradient coils around my head
like some horror mask: noisy and boring.

John

Noisy & boring is right. I fell asleep briefly and was mildly scolded
for it - they could see my eyeballs rolling around.

 

[Bob Eld]

That's probably because you guys don't have a house with a narrow crawl
space. At least you can be sure that there won't be critters such as
rattle snakes waiting inside that MRI tube.

I had a rattle snake in my garage a couple of weeks ago.

 

[Dirk Bruere at NeoPax]

Pulsed gradient coils. These are "small" 3-axis coils that sweep a
gradient field across your innards, modulating the nuclear resonant
frequencies of your molecules to produce the spatial resolution. These
are generally water-cooled, with ballpark 20 KW constant-current
drivers per axis, playing all sorts of weird waveforms.

They scanned my head last year, with the gradient coils around my head
like some horror mask: noisy and boring.

Any obvious neural effects from the scanning fields?

 

[Dirk Bruere at NeoPax]

That's probably because you guys don't have a house with a narrow crawl
space. At least you can be sure that there won't be critters such as
rattle snakes waiting inside that MRI tube.

Is that because they check them every morning?

 

[RFI-EMI-GUY]

It's coming off the gradient magnets, usually. I hope all is ok and you
won't receive any nasty diagnosis from the session.

Thanks, nothing serious except a bad pain in my neck C5/C6 disk
problems. It was a bit disheartening to hear the technician say "that
looks real bad, you should get that fixed" Then I remembered she said
same thing two years ago. The Dr reports it is same as before, only now
it hurts worse. I guess I gotta do something

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

 

[RFI-EMI-GUY]

Pulsed gradient coils. These are "small" 3-axis coils that sweep a
gradient field across your innards, modulating the nuclear resonant
frequencies of your molecules to produce the spatial resolution. These
are generally water-cooled, with ballpark 20 KW constant-current
drivers per axis, playing all sorts of weird waveforms.

They scanned my head last year, with the gradient coils around my head
like some horror mask: noisy and boring.

John

Are they inside the machine or are they in the frame clamped around my
head and neck?

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

 

[RFI-EMI-GUY]

A few years ago they scanned my sinuses.

I must admit a claustrophobic feeling also :-(

...Jim Thompson

I told the tech to give me a time check every so often so I wouldn't
lose my mind, then I worked out a design problem in my head for 30
minutes as a distraction. I can put up with a lot of stuff but being
inside or under that thing creeps me out. I keep having visions of
oxygen cylinders getting sucked through the drywall and crushing me or
the magnet quenching and getting burned in a puff of steam.

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

 

[Joerg]

Thanks, nothing serious except a bad pain in my neck C5/C6 disk
problems. It was a bit disheartening to hear the technician say "that
looks real bad, you should get that fixed" Then I remembered she said
same thing two years ago. The Dr reports it is same as before, only now
it hurts worse. I guess I gotta do something

They should never say that. It's almost like a surgeon saying "Oh s..t!
That wasn't good."

Must be painful. My sore ones are L4/L5/L6. The docs never figured out
that I might have a magnesium deficiency. A CPA (!) gave me that hint.
Taking them big Costco pills since two years. Knock on wood, in those
two years it hasn't floored me once and that's a record.

 

[krw]

Pulsed gradient coils. These are "small" 3-axis coils that sweep a
gradient field across your innards, modulating the nuclear resonant
frequencies of your molecules to produce the spatial resolution. These
are generally water-cooled, with ballpark 20 KW constant-current
drivers per axis, playing all sorts of weird waveforms.

They're moving? Wires loose? It certainly is noisy.
I went into the tube last year. I'm pretty claustrophobic, but
handled it OK. Not a chance of sleeping though. I certainly was
ready to come out after a half-hour.

They scanned my head last year, with the gradient coils around my head
like some horror mask: noisy and boring.

Find anything? ;-)

 

[JeffM]

They scanned my head last year

....and found nothing?
SCNR. I'm surpirsed no one else took the shot.

 

[Dirk Bruere at NeoPax]

Well, bits of him twitching abnormally might be a sign.
Google TMS

 

[Clifford Heath]

No, it's full of all sorts of gooey and gooshy stuff.

Google "They're made out of meat"

 

[Clifford Heath]

Messy wet stuff. I prefer electronics.

You miss my point. It's a cute and classic piece of writing:

<http://www.terrybisson.com/meat.html>

Clifford Heath.

 

[Spehro Pefhany]

What an absurd fear. It quenches, a lot of cold helium blows out, the
O2 in the room is displaced, and you die painlessly of asphixiation.

John

There are a number interesting modes of dying involving cryostats.

Best regards,
Spehro Pefhany

 

[Joerg]

What an absurd fear. It quenches, a lot of cold helium blows out, the
O2 in the room is displaced, and you die painlessly of asphixiation.

Look at the bright side: Until you lose consciousness you can speak at a
high pitch like Mickey Mouse because of the helium. Should be fun ;-)

 

[T]

You miss my point. It's a cute and classic piece of writing:

<http://www.terrybisson.com/meat.html>

Clifford Heath.

And made into video too:

 

[T]

There are a number interesting modes of dying involving cryostats.

I had a full head MRI about a year ago. I don't suffer claustrophobia
and can tune out pretty much any noise. They actually had to nudge me
awake to put the gadolinium contrast IV in.