Functional magnetic resonance imaging (fMRI) is a relatively new procedure that uses MR imaging to measure the tiny metabolic changes that take place in an active part of the brain.
A magnetic resonance imaging (MRI) scan is a painless procedure that lasts 15 to 90 minutes, depending on the size of the area being scanned and the number of images being taken.epending on the size of the area being scanned and how many images are taken, the whole procedure will take 15 to 90 minutes. The MRI scanner will make loud tapping noises at certain times during the procedure.
Breast MRI overview. 1  An MRI machine produces a strong magnetic field and radio waves. 2  MRI does not use X-ray radiation. 3  Breast MRI is not better than mammography, just different.  Exams typically take 45 1  minutes. Breast MRI always involves contrastâan injection that makes the images more vivid and informative.