Magnetic susceptibility is dimensionless proportionality constant that indicates the degree of magnetization of a material in response to an applied magnetic field (wikipedia). As the name suggests, Susceptibility Weighted(SW) MR imaging is a method of brain imaging in which the intensity of a particular voxel is proportional to the magnetic susceptibility of the underlying tissue. Because de-oxygenated venous blood is rich in iron content than neighbouring tissues, the magnetic property is also substantially different which is why SW images are used for a good understanding of the distibution of veins in the brain.
In our experiment full-brain volumetric images (512x512x500) in NIfTI format were recorded with a Philips MR scanner at 3 Tesla using a 3D Presto FFE sequence (0.43x0.43x0.3 mm voxel size). Facial features have been removed from these images for de-identification. Separate phase and magnitude images are provided. The next section gives the details of 2 methods used for processing the SW images thus acquired.