I had an MRI on my back recently and the doctor played me the CD of my scan in his consulting rooms and showed me the narrowing of the space between the vertabra which i could see perfectly,then he showed me the bulging disc and then he showed me all the nerves from the spine to my legs.It gave me a very clear picture of bone,tissue and nerves.

I would wait until the last minute to get any scan post Tx. I had 3 CT's and the first 2 produced words like..."an area that can not be excluded". Believe me those are words you definitely don't want to deal with a few months post Tx. Each time my docs would say "nothing to worry about, probably just inflammation. We'll wait a few more months and do another one."

Oh yeah fine, you tell me that IF my cancer comes back it will be sooner rather than later and you tell me I have AREAS THAT CAN NOT BE EXCLUDED and you tell me NOT TO WORRY. Pins and needles for me for 3 CT's until the last one was all clear.

Markus: could you explain more about an MRI. I'm thinking about asking for one after treatment. Thanks Sandy

What is an MRI scan?

MRI (magnetic resonance imaging) is a fairly new technique that has been used since the beginning of the 1980s.

The MRI scan uses magnetic and radio waves, meaning that there is no exposure to X-rays or any other damaging forms of radiation.

How does an MRI scanner work?

The patient lies inside a large, cylinder-shaped magnet. Radio waves 10,000 to 30,000 times stronger than the magnetic field of the earth are then sent through the body. This affects the body's atoms, forcing the nuclei into a different position. As they move back into place they send out radio waves of their own. The scanner picks up these signals and a computer turns them into a picture. These pictures are based on the location and strength of the incoming signals.

Our body consists mainly of water, and water contains hydrogen atoms. For this reason, the nucleus of the hydrogen atom is often used to create an MRI scan in the manner described above.

What does an MRI scan show?

Using an MRI scanner, it is possible to make pictures of almost all the tissue in the body. The tissue that has the least hydrogen atoms (such as bones) turns out dark, while the tissue that has many hydrogen atoms (such as fatty tissue) looks much brighter. By changing the timing of the radiowave pulses it is possible to gain information about the different types of tissues that are present.

An MRI scan is also able to provide clear pictures of parts of the body that are surrounded by bone tissue, so the technique is useful when examining the brain and spinal cord.

Because the MRI scan gives very detailed pictures it is the best technique when it comes to finding tumours (benign or malignant abnormal growths) in the brain. If a tumour is present the scan can also be used to find out if it has spread into nearby brain tissue.

The technique also allows us to focus on other details in the brain. For example, it makes it possible to see the strands of abnormal tissue that occur if someone has multiple sclerosis and it is possible to see changes occurring when there is bleeding in the brain, or find out if the brain tissue has suffered lack of oxygen after a stroke.

The MRI scan is also able to show both the heart and the large blood vessels in the surrounding tissue. This makes it possible to detect heart defects that have been building up since birth, as well as changes in the thickness of the muscles around the heart following a heart attack. The method can also be used to examine the joints, spine and sometimes the soft parts of your body such as the liver, kidneys and spleen.

How does an MRI scan differ from a CT scan?

With an MRI scan it is possible to take pictures from almost every angle, whereas a CT scan only shows pictures horizontally. There is no ionizing radiation (X-rays) involved in producing an MRI scan. MRI scans are generally more detailed, too. The difference between normal and abnormal tissue is often clearer on the MRI scan than on the CT scan.

How is an MRI scan performed?

The scan is usually done as an outpatient procedure, which means that the patient can go home after the test. During the scan it is important to lie completely still. For this reason it might be necessary to give a child an anaesthetic before they are tested.

Since you are exposed to a powerful magnetic field during the MRI scan, it is important not to wear jewellery or any other metal objects.

It is also important for the patient to inform medical staff if they use electrical appliances, such as a hearing aid or pacemaker, or have any metal in their body such as surgical clips, but orthopaedic metalware such as artificial hips or bone screws is not normally a problem.

Is an MRI scan dangerous?

There are no known dangers or side effects connected to an MRI scan. The test is not painful; you cannot feel it. Since radiation is not used, the procedure can be repeated without problems. There is a small theoretical risk to the foetus in the first 12 weeks of pregnancy, and therefore scans are not performed on pregnant women during this time.

Because patients have to lie inside a large cylinder while the scans are being made some people get claustrophobic during the test. Patients who are afraid this might happen should talk to the doctor beforehand, who may give them some medication to help them relax.

The machine also makes a banging noise while it is working, which might be unpleasant.


Based on a text by Dr Carl J Brandt, GP

Liz:
Thank you so much for taking the time to write all that. It was very helpful.
Thanks
Sandy

Excellent description by Liz.
There is nothing really to add unless you want to get technical. The magnets are currently up to about 4 Tesla (about 30'000 times stronger than the earth magnetic field). Hydrogen atoms are little magnets that either point up or down when exposed to an external field. (A testament to the quantum nature of the world). You measure the signal when they flip back after a radio frequency pulse. Why the noise.... In order to localize the signal (i.e. get a picture) one applies strong currents to a coil for a short time. (Hence the woodpecker noise).

Seriously cool stuff ....

A drawback is that it takes relatively long to take a scan and that these things are very expensive to maintain. The powerful ones are all superconducting and contain liquid helium (about 4.2 K, or -269 deg C). Unless you have an electronic implant or a ferromagnetic material there is no real problem.


M

There was a janitor cleaning the area of the MRI machine a few years ago , at The UPMC, a well know hospital in Pittsburgh . Somehow, he was close to the machine and someone either left it on or he accidently activated it, and it suck him part way into it. He had too much metal on or in his clothes. LOL he was unijured fromm his ordeal but was shaken up very bsd. It was in the news in our area. Yep, leave you metel at ho,ome or make sure you give it to the nurse doing the procedure. I had a DR asked me if I had problems in the machine because I have a staple in one shoulder and a screw and washer in the other, LOL I guess he didn't learn that stainless steel doesn't get pick up with a magnet.

Jim,
actually you cannot just turn these things off, not if they are superconducting. We guard our NMRs like hawks, have combination locks and any number of warning signs. Even so you have to make damn sure people just do not walk up to it....

M

Jim, you might want to read this about stainless steels and magnetism:

http://www.azom.com/details.asp?ArticleID=1140

This topic came up on an RV group the other day and I checked my flatware drawer -- All marked SS, but some utensils very magnetic, some not so much and some not all all, all from same manufacturer.

Thanks pete, I just read it and relearned about stainless. The oly thing thaty bothers these stainless steel parts, is when I accidently hit my shoulder with the staple against something . I did this the other dsy onm a door and am going crazy with the pain I caused myself. It hurts more when I sit still so I keep busy.