Extraspinal abnormalities detected on MR images of the spine

Surface-coil MR imaging of the spine is one of the most commonly performed MR imaging procedures. As the spine is the region of interest in these studies, extraspinal abnormalities may be overlooked. Such lesions can be difficult to perceive because they are out of the area of interest or distant from the surface coil. MR studies may be interpreted without other radiographic studies for comparison, as the other studies often have been performed elsewhere. Consequently, it is important for radiologists to be aware of the extraspinal anatomy and the appearances of extraspinal abnormalities. We describe the appearances of some common extraspinal diseases and normal variants detected with surface-coil MR imaging of the spine.