An MRI (Magnetic Resonance Imaging) is a non-invasive method of scanning soft tissue. It uses only magnetic and radio waves, so there is no exposure to any form of radiation.
To perform the scan, you will lie on a movable table that will slide into a cylindrical tube that is actually a large magnet. Once you are inside, radio waves that are between 10,000 to 30,000 times stronger than the magnetic field of the earth are broadcast through your body. These are harmless and you will not feel anything. These waves force the nuclei of the atoms inside your body’s cells into a different position. As they shift back into their normal position, their movement emits radio waves of their own, which a computer uses to assemble an image. Depending on what is being scanned, an MRI scan may take anywhere from ten minutes to almost an hour.
An MRI is a noisy procedure, and some people may feel claustrophobic while in the tube. I recommend two methods to counter this claustrophobic feeling. One is to close your eyes and picture yourself somewhere else that is pleasant. Also, you may be able to manage to look up behind your head and see outside the tube. Sometimes, for parts of the procedure, you may be able to relax your body and take a short nap, so that when the MRI is completed you feel rested. Since the sound of the machine is very loud, you may be offered earplugs, or in some facilities, headphones with music to block out the sound. If your facility offers the headphones, bring in a CD of your favorite relaxing music.
You can tell the MRI operator to pull you out of the tube at any time
An MRI scan is capable of creating images of almost all the different types of tissue in your body, as well as tissue that is surrounded by bone. Even the tissue in your skull (your brain) and spinal column can be visualized.
An MRI procedure may also use contrast agents to highlight a particular organ or specific type of tissue. (The contrast material is often also called “dye.”) Make sure you tell your doctor when prescribing the MRI if you have ever had an allergic reaction to other contrast materials; shellfish; or if you have any metal in your body or kidney problems. Tell the technician the same thing as well before starting the MRI. Certain MRI procedures will also use a coil that is inserted into the rectum to better visualize that area of your body. This is increasingly common when the prostate area is being imaged.
The good news is that MRI technology is getting better. Many facilities now have machines with greater sensitivity and use new, significantly more sensitive contrast materials (dyes).
MRI (Magnetic Resonance Imaging) uses magnets rather than X-rays to create a detailed picture of your prostate and surrounding tissues. You may have an MRI if there is a risk of your cancer spreading and you are considering active treatment options such as radiotherapy or radical prostatectomy.
You will need to take off any jewellery or metal items that could be attracted to the magnet. You will also be asked questions about your health and whether you have any implants, such as a heart pacemaker, to make sure the scan does not harm you.
Some MRI scanners are doughnut-shaped like a CT scanner. Other MRI scanners are shaped like a long tunnel so much more of the machine covers your body than in a CT scanner. Ask which type of machine is used at your hospital so you know what to expect. If you suffer from a fear of enclosed spaces (claustrophobia), you should let the scanning department know as soon as possible.
You will be asked to lie on a table which passes into the tunnel and you may feel totally enclosed. Some people can find this claustrophobic but the staff are aware of this and will help you if you become uncomfortable during the scan. The radiographer may decide to give you an injection of a dye during the scan, if they think that this will help improve the pictures taken by the scanner.
The scan takes between 30 and 40 minutes. The machine is very noisy but you will not feel anything. You can speak to the staff through a microphone and you may be able to listen to music. You can take a friend or family member into the room with you while you have the scan if you would like.