Susceptibility Weighted Imaging (SWI)
Sequence: Susceptibility weighted
Abbr.: SWI
Physics: Sensitive for blood and calcium, by a fully flow compensated, long echo, gradient recalled echo (GRE) pulse sequence to exploit magnetic susceptibility differences between tissues
Main Clinical distinctions: Detecting small amounts of hemorrhage (diffuse axonal injury pictured) or calcium.
Susceptibility-weighted imaging (SWI) is a new type of contrast in MRI different from spin density, T1, or T2 imaging. This method exploits the susceptibility differences between tissues and uses a fully velocity-compensated, three-dimensional, RF-spoiled, high-resolution, 3D-gradient echo scan. This special data acquisition and image processing produces an enhanced contrast magnitude image very sensitive to venous blood, hemorrhage and iron storage. It is used to enhance the detection and diagnosis of tumors, vascular and neurovascular diseases (stroke and hemorrhage), multiple sclerosis, Alzheimer's, and also detects traumatic brain injuries that may not be diagnosed using other methods.
