What is the difference between an MRI and a Cat Scan?

Question

I know that one uses Computer and the other uses Radio waves. I did a cat scan without contrast and it showed liver enlarged. (Radiologist said) Doctor never seen it since it got lost. He sent me for another cat scan with contrast and it was normal. Liver enzymes were slightly elevated. I was still in pain so I went to the hospital and they did a songram which showed the liver enlarged. I want to know how come it didn't show up enlarged on the cat scan but on the sonogram it did? Liver tests showed normal. Would anything different show up if I took an abdominal MRI? I took an MRI of the spine because the doctor thinks it might be a pinched nerve and he is not worried about the liver because the cat scan came out normal. Who do I trust? The Cat Scan or Sonogram?

Answer 1

I'm not comfortable trying to evaluate your tests but I'll tell you the difference.

MRI is using radio waves where the protons are excited and give off energy which is detected external to the body where their signal is interpreted

Cat or CT(you'll hear both terms) are x-rays. The x ray source spins around you and based on the attenuation in the body. An image is reconstructed.

Sonograms are rather iffy since you need to remember, a lot of that stuff in the abdomen won't have any difference in their properties under US(sonogram) unless you're looking for something specific.

The major difference between CT and MR is in the soft tissue contrast. With CT, it's wonderful for its speed and for distinguishing problems due to emergent situations since the attenuation difference is great between tissue and bone. However, it sucks for differentiating soft tissues. It's not easy to see a noticeable difference between liver and stomach for example since they attenuate about the same in terms of x-rays.

MRI is slow so its not good in ER situations however it provides a wealth more information since there is a difference based on healthy versus patholoigal tissue. There WILL BE A DIFFERENCE IN WHAT CAN BE SEEN IN AN MRI DUE TO THE BETTER CONTRAST.

It's possible the liver enlarged in the interim between your tests. Additionally, there is some physiologcal variation based on diet, time of day, lots of factors....

Shoud you have the MRI?

Based on the fact that the doctors don't seem to have a clear picture on what's going on, the MRI will provide them with more information so it might be useful. Will it be definitive? Probably not, the best information for liver and kidney stuff still seems to be chemical rather than imaging.

Answer 2

Computed tomography (CT) a method of body imaging in which a thin x-ray beam rotates around the patient. Small detectors measure the amount of x-rays that make it through the patient or particular area of interest. A computer analyzes the data to construct a cross-sectional image. These images can be stored, viewed on a monitor, or printed on film. In addition, three-dimensional models of organs can be created by stacking the individual images, or "slices." MRI is a non-invasive procedure that uses powerful magnets and radio waves to construct pictures of the body. Unlike conventional radiography and computed tomographic (CT) imaging, which make use of potentially harmful radiation (x-rays), MRI imaging is based on the magnetic properties of atoms. A powerful magnet generates a magnetic field roughly 10,000 times stronger than the natural background magnetism from the earth. A very small percentage of hydrogen atoms within a human body will align with this field. Please see the web pages for more details on CAT scan and MRI scan.

Answer 3

MRI's or Magnetic Resonances Imaging in three dimensional and deep scanning will be the future. They no longer give you a handful of X-Ray photos but only a disc with interpretations on a computer.
The old huge MRI is on the way out, along with CATS. The new MRI is small and quick and above all, super quiet. There no longer a tube you have to be shoved into while that firing of the MRI sounds like machine gun rapid fire and very scary to especially children.

The new three dimensional pictures are very real, like the organ itself is out of the body and can be turned and twisted to the doctors advantage.

A radiologist should have read your scans, the interpretation is usually left to an expert. If your not comfortable with this ask your doctor and tell him your fears.
He should be able to give you an personal opinion of what is shown.

Answer 4

I don't know how to answer that question. If it were me, I'd see another doctor and get a second opinion. Tell the second doctor about the different tests. He or she should be able to look at those so they don't have to be repeated.

Answer 5

Cat Scans are usually x-rays of your brain and the MRI's are of the spinal cord.

Answer 6

I have no knowledge of any of this, but I think that cat scans scan your head/brain, and mri's are for your body, shoulder's down.

Answer 7

http://www.letsgooutdoors.net/difference-between-mri-and-ct-scan.htm

This will explain everything.