Susceptibility Weighted Imaging
Susceptibility weighted imaging (SWI) is a relatively new magnetic resonance (MR) technique that provides innovative sources of contrast enhancement visualizing the changes in magnetic susceptibility that are caused by different substances like iron, hemorrhage or calcium. The detection of micro-hemorrhages, shearing, and diffuse axonal injury (DAI) in trauma patients is often difficult as the injuries tend to be relatively small in size and can be easily missed by low resolution scans. SWI is usually run at relatively high resolution (1 mm3) and is extremely sensitive to bleeding in the gray matter/white matter boundaries making it is possible to see very small lesions increasing the ability to detect more subtle injuries. SWI is used to help diagnose Traumatic Brian Injuries, Stroke, Occult Vascular Disease and Tumors.