Magnetic Resonance Imaging (MRI) is a noninvasive medical test that helps physicians diagnose and treat medical conditions. 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, transmitted electronically, printed or copied to a CD. MRI does not use ionizing radiation (X-rays). Detailed MR images allow physicians to better evaluate various parts of the body and determine the presence of 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 any of the lower extremities when examining the:
MR imaging is typically performed to diagnose or evaluate:
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.
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. If a contrast material is used during the examination, it will be injected into the intravenous line (IV) after an initial series of scans. Additional series of images will be taken during or following the injection. 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 30 to 45 minutes. In selected patients, conventional arthrography will be performed first. During that procedure contrast material may be injected into the joint of concern (typically in the shoulder, hip or wrist) before MRI in order to image the joint structures in more detail.