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.
Rating Newest Oldest. Best Answer: A MRI of the knee will take anywhere from 30-60 minutes, depending on the machine used and how many imaging sequences are done. You will need to call the imaging facility, where you are having your MRI. They will tell you how long it takes to do this scan at their facility.