[andrzejpw]

they took an MRI of my brain today. A couple of questions:

most importantly, even though I was wearing earplugs, how loud do those machines get? I'm not feeling any adverse effects, but just in case. . .

How do they work? I take it theres an electromagnet inside. . . does it see how much you influence the environment?

Any problems that could result from having one done?

 

[elipsis]

I hear they make you paranoid about possible side effects.

 

[andrzejpw]

Ah well, guess I deserved that.

I've never had one, sorta weird.

 

[zbuddah]

so what was the reason for the MRI?

 

[kelly]

I heard Syd Barret had an MRI once.

 

[CaptBubba]

Quote:

Originally posted by andrzejpw How do they work? I take it theres an electromagnet inside. . . does it see how much you influence the environment?

MRI stands for Magnetic Resonance Imaging. Here's basically what happens (if I remember right):

Big, really powerful magnet turns on.

The electrons in whatever is being scanned change their quantum spin to match up with the magnetic field.

Magnet turns off, sensor turns on.

Electrons fall back to thier initial spins, releasing energy which is picked up by the sensor. More energy is released by denser matter.

Computer takes the boatload of data and forms a picture.

Of course, I can't remember exactly. I may be confusing this with PET or CAT scans, but I'm pretty sure this is the right thing. Remember that there are actually multiple theories as to how they work, each with its strong and weak points.

MRIs have been conclusivly linked to large lightening of the wallet, those scans are expensive! Even with insurance they ain't cheap.

 

[bifcake]

MRI is sort of like having a really big and really powerful cell phone. It probably causes cancer of the brain, but I would imagine you'd have to be exposed to it for more than a minute.

 

[Audio Redneck]

I double checked with the head nurse and CaptBubba is right on the money with his explaination. Different parts of the body have differing amounts of iron and other manetically polarized elements. And since every cell gets blood, which has iron in it, every part of the body can be imaged. And No radiation involved at all.

Sorry Bifcake, you've got MRI and X-rays mixed up.

So whats up Andrezj? You don't give a 16 year old an MRI for the fun of it.

 

[mbriant]

Quote:

Any problems that could result from having one done?

Metallic objects might stick to your head.

Seriously though, I hope everything checks out OK for you.

 

[Russ Arcuri]

Well, just to make you a little bit more paranoid... What we call MRIs used to be called NMRIs. They changed the name because public perception of the old name invoked fear.

MRI = Magnetic Resonance Imaging
NMRI = Nuclear Magnetic Resonance Imaging

Of course, no matter what you call it, it's a very useful diagnostic tool for doctors and is considered quite safe.

I'm guessing you had a head injury that resulted in a brief loss of consciousness. Standard procedure is to evaluate you and do an MRI to check for problems in your cranium.

 

[redshifter]

yeah, aren't mri's a blast? i still have the pictures from mine. it really wierded me out, seeing my brain like that.

i also had a test at the ear doctor once, where they have you take some valium, lie down, and stick electrodes in your ear. they then proceed to send small shocks into your ear cavity to scan for anything unusual. man, that was unpleasent.

 

[nanahachi]

i had an MRI done when gravity decided to help me smack my head on the ground, resulting in a concussion and shattering the paperthin bone btwn the sinus cavity and the eye

it was actually a pretty cool experience, the MRI, that is.

in fact, without it, i probably wouldnt have inherited my superpower of meta-human indecisiveness.

 

[gerG]

Nope, no after-effects.

Well, except for a craving for single malt whiskey...

and obsessive audio syndrome...

and recalcitrant disregard for speed limits...

...at least there were no bad after-effects.

gerG

 

[The Quality Guru]

The scariest part of an MRI is the fear of something metalic in the room that could be magnetically attracted to you and kill you. For if there is something meade of metal in the room (watch, scissors, coin) you're almost guaranteed to get quite hurt or die. Accidents like this (due to carelessness) don't occur too frequently, but just hope that the technoligist isn't a doofy. My mom is a radiologist, so she enlightens me about all the crap that goes on at the hospital.

 

[Hirsch]

MRI does not have anything to do with iron. The magnetic beam is deflected by hydrogen protons. What it actually measures is the water density in a given area of tissue.

You are not going to become magnetic by being in an MRI tube. Nothing gets attracted to you. However, you will be in the middle of a large magnet. If you are between the magnet and a metal object when the magnet goes on, you could be in trouble, as that object is going to travel in a straight line to the magnet. However, the inverse square law works, and an object will have to be pretty close to the magnet for this to be an issue. Also note that while you may not be much of an obstacle to a flying metal object, the MRI tube is.