Is a CAT-Scan an MRI? nt

[Eric J in MN]

nt

[purji]

1. no n/t

n/t

[Deep13]

2. No

CAT scan (I forgot what the acronym stands for) is Xray. MRI is magnetic resonance imaging. Each system detects a different kind of radiant energy.

[WillowTree]

6. CAT...

....stands for Computer Assisted Tomography, or sometimes Computed Axial Tomography. Both refer to the same thing.

Tomography refers to x-ray imaging performed in sections. A CAT Scan produces an image which is like viewing a slice of the organ or body section as opposed to a regular, two-dimensional x-ray.

[Ironpost]

3. I understand they're different

had a CAT-scan of my lunges a few years back. I go in this evening for an MRI of my lower back.

[markbark]

4. The Diff is:

CAT stands for Computer Aided Tomography.
It's a very high resolution X-Ray.

MRI stands for Magnetic Resonance Interferometry.
That uses big honkin' magnets whose alternating/varying fields make hydrogen atoms wiggle in the item being scanned these wiggling atoms set up tiny electrical fields when they snap back to their original orientation thus giving the machine a signal to read.


--MAB


edit for typos

[OrlandoGator]

5. With a CT scan, you have to have contrast agents in your system.

A CT scan is a high-resolution X-ray that picks up dyes and other contrast agents in your body that are swallowed or injected intravenously.

An MRI is a digital image of induced magnetic resonances in the body.

[WillowTree]

7. If that's true...

....then the nature of CAT scans has changed because I've had them with and without contrast. Same with MRIs.

[OrlandoGator]

8. It's possible that there are new CT's that don't require it.

I had a lower-torso CT last week, I had to drink two large bottles of barium and get a dye IV. Different body parts may require different contrast agents (or none at all).

[AngryAmish]

9. Contrast agent is not always used

Depends on the particular scan.

[OrlandoGator]

10. I was only speaking from my recent experience, I stand corrected.

n/t

[AngryAmish]

11. Quite all right

I'm not a doctor, but I deal with a lot of medical stuff in my job.

[Jim Lane]

12. Contrast usually improves the image

I had a CAT scan without the dye because they wouldn't give it to me when they found I was asthmatic (it can cause problems). For the next one I had, I premedicated with Prednisone so that I could receive the dye. I saw both images and the second one was much sharper.

[AngryAmish]

13. It depends on what you are imaging

Again, I'm not a doc, but if all the structures have a lot of blood vessels it does little good and not worth the risk from the contrast material.

[Ilsa]

14. There are also PET scans, which use a glucose-based radioiostope

The radiosisotope circulates and causes the soft tissues to give off low level gamma emissions. Since quickly growing cancers absorb alot of the solution, they give off a stronger signal. Therefore it is used alot for examining for cancer, etc.

[Redstone]

15. Does anyone else remember when MRI was called

NMR (Nuclear-Magnetic Resonance)?

I worked with GE (as a vendor) when they were developing the first of these machines; it didn't take them too long to figure out that they weren't going to sell any machines with "nuclear" in the name, even though in this case it referred to the nucleus of a cell.

Redstone