MRI stands for magnetic resonance imaging and for now it's the medical profession's best tool to see what's inside your body. Let's say it beats cutting you open to look inside.
Some advantages of MRI include diagnosing strokes in their earliest stages; diagnosing MS (multiple sclerosis); diagnosing brain and pituitary tumors; diagnosing brain, spine, or joint infections; visualizing torn ligaments in the wrist, knee, and ankle (sports player use MRIs); visualizing shoulder injuries; diagnosing tendonitis; evaluating soft tissue masses; and evaluating bone tumors, cysts, and herniated discs in the spine.
MRI systems do not use ionizing radiation as MRI contrast materials have a very low incidence of side effects. Another advantage of a MRI is its ability to image in any plane. CT scans are limited to one plane, the axial plane. An MRI system can create axial images.
Like anything MRI also has disadvantages: People with pacemakers cannot have MRIs. Also some people who are morbidly obese cannot fit in into an MRI system. Claustrophobic patients cannot usually make it through a MRI. The machine makes a tremendous amount of noise during a scan. The noise sounds like a continual, rapid hammering. Patients are given earplugs or stereo headphones to muffle the noise (in most MRI centers you can even bring your own cassette or CD to listen to). The noise is due to the rising electrical current in the wires of the gradient magnets being opposed by the main magnetic field. The stronger the main field, the louder the gradient noise.
MRI scans require patients to hold still for extended periods of time. MRI exams can range in length from 20 minutes to 90 minutes or more. Even very slight movement of the part being scanned can cause distorted images which means the scanning will need to be repeated. Orthopedic hardware (screws, plates, artificial joints) in the area of a scan can cause severe distortions on the images. MRI systems are very expensive; therefore the exams are also very expensive. Will your health insurance pay for that?
Lastly, people with kidney disease or on dialysis or people who didn't know they had kidney disease are likely to develop an incurable condition called Nephrogenic Systemic Fibrosis (NSF) from the MRI dye injection gadolinium. NSF causes a hardening or stiffening of the skin and joints. If this has happened to you, consider contacting a lawyer familair with NSF Gadolinium Lawsuits.
MRI advantages far outweigh the disadvantages - that is of course, if you don't have kidney disease.