Medical imaging began with the X-ray a little more than 100 years ago, but since then many strides have been made that allow doctors to see under the skin of their patients without the use of invasive exploratory surgery. One of the most important and fascinating of the new technologies emerged in the early 1970s: magnetic resonance imaging (MRI) scan.
This method offers a slightly different advantage in helping physicians to diagnose disorders, including many conditions that are life-threatening. It often enables doctors to spot diseases in their early, curable stages, and they can also quickly rule out a suspected disorder.
Unlike X-rays and the computed tomography (CT) scans, MRIs do not involve radiation. As the patient lies within a large device – usually a cylindrical machine – powerful magnetic fields trigger painless vibrations in atoms of the body. These vibrations give off signals that are relayed to a computer and ultimately translated into two- and/or three-dimensional images. The pictures can be made from any direction and in any plane, allowing once-impossible views of multiple angles. The MRI images can be more detailed than those of CTs and show more differentiation within the body’s soft tissues.
Currently, MRI tests are most often used to diagnose brain and nervous-system disorders, joint and muscle abnormalities, and tumors of the liver, kidney, bladder, pancreas, reproductive organs, lymph nodes, and vocal cords. Most recently, MRIs have begun to play a role in the diagnosis of heart disease, particularly the type that affects blood vessels, with a procedure known as the MRI angiogram.
While MRI scans are relatively safe and painless, some safety precautions still need to be observed:
1) When undergoing an MRI, be sure to let your doctor know if you have a metallic joint replacement or any other type of metallic device. The scanner could adversely affect these appliances. Jewelry, clothing with zippers, and other metallic objects must be removed before an MRI test.
2) Tattoos and MRIs also don’t mix. Tattoo inks often contain metals that can interact with the magnetic fields and create an intense heat that results in painful burning and swelling.
3) Most MRIs require that patients lie virtually motionless in a tunnel-shaped machine that sometimes causes a frightening bout of claustrophobia or a high level of anxiety in many patients. To help patients, doctors sometimes prescribe a tranquilizer prior to the scan.
4) Some doctors also offer patients headphones so that they can listen to music that helps block out the loud clanking noises produced by the machine.
5) Patients are usually provided with a signal button or some other device so they can alert the MRI staff if they begin to feel uneasy during the test.
If you feel a traditional MRI machine will make you uncomfortable, ask your doctor if the so-called open MRI machines, whose "tunnel" is roomier than those of standard machines, are available in your area. (They are not commonly in use.) Although these newer machines were once considered less effective than the closed ones, advances have made them acceptable for diagnosing many conditions. Halfway between the standard and the open MRIs are those that use smaller tunnels, which encase only the part of the body that is being scanned.
Great post! You have made some really great points here. Most MRI scans take between 20-60 minutes and patients should experience no discomfort. They will, however, hear a loud knocking or tapping sound when the scanner is actually acquiring information. Although MRI has become a well accepted imaging modality, it does have some degree of risk for the patient. I think these safety tips are really useful for people. Thanks!