An fMRI of the Brain is called Functional Magnetic Resonance Imaging (fMRI), which 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. MR imaging uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, bone and virtually all other internal body structures. The images can then be examined on a computer monitor, printed or copied to CD. MRI does not use ionizing radiation (X-rays). Detailed MR images allow physicians to better evaluate various parts of the body and certain diseases that may not be assessed adequately with other imaging methods such as X-ray, ultrasound or computed tomography (also called CT or CAT scanning).
Your doctor may recommend a MRI of the brain (fMRI) as it is becoming the diagnostic method of choice for learning how a normal, diseased or injured brain is working, as well as for assessing the potential risks of surgery or other invasive treatments of the brain.
Physicians perform fMRI to:
MRI examinations may be performed on outpatients or inpatients. You will be positioned on the movable examination table. Straps and bolsters may be used to help you stay still and maintain the correct position during imaging. Small devices that contain coils capable of sending and receiving radio waves may be placed around or adjacent to the area of the body being studied. For fMRI, your head may be placed in a brace designed to help hold it still. This brace may include a mask that is created especially for you. You may be given special goggles and/or earphones to wear, so that audio-visual stimuli (for example, a projection from a computer screen or recorded sounds) may be administered during the scan.
If a contrast material will be used in the MRI exam, a nurse or technologist will insert an intravenous (IV) line into a vein in your hand or arm. A saline solution may be used. The solution will drip through the IV to prevent blockage of the IV line until the contrast material is injected. You will be moved into the magnet of the MRI unit and the radiologist and technologist will leave the room while the MRI examination is performed. During an fMRI exam, you will be asked to perform a number of small tasks, such as tapping your thumb against each of the fingers on the same hand, rubbing a block of sandpaper or answering simple questions. When the examination is completed, you may be asked to wait until the technologist or radiologist checks the images in case additional images are needed. Your intravenous line will be removed. MRI exams generally include multiple runs (sequences), some of which may last several minutes. The entire examination is usually completed within 45 minutes.