Not many are aware what an MRI is unless you are asked to go for an MRI. MRI is Magnetic Resonance imaging a painless technique used by the doctors to have a look at the tissues of the body. This is different from X-rays. MRI will give a clear picture of the tissues that cannot be felt or touched by hands. This was initially used to diagnose about the knee injuries. The machines make use of the radio waves and magnetic fields. MRI has gained popularity as it does not have any radiation that is harmful and is non-invasive. This will give a detailed image of the blood vessels, tissues, bones and other internal organs.