However, the MRI is not always the first test given since it is more expensive and generally takes longer than the X-rays or CT scans. Instead of radiation, a MRI uses magnetic waves to take pictures of the spine. A magnet excites the hydrogen atoms in the body, which give off electromagnetic waves that are recorded by a computer. The computer then analyzes the results to reconstruct an image of the spine. The MRI scanner is a large tube with a table passing through it.
Some people worry about feeling closed in, however, the tube always remains open on both ends.
You won t feel any pain, but you will hear some loud noises during the exam. Depending on how many pictures are needed, the exam can take anywhere from 20 minutes to 90 minutes. It is very important that you notify your physician if you have any metal in your body which cannot be removed, such as a pacemaker, aneurysm clips or a prosthesis. You may not be able to have an MRI if you have such metal in your body. Leave your jewelry at home, and remove all metallic objects such as hearing aids and dentures before entering the scanning room.