Object orientation independence of Susceptibility Weighted Imaging by using a Sigmoid-type phase window
Swanson S, Noll D, Martinez Santiesteban F, Anderson D
University of Michigan
Susceptibility Weighted Imaging (SWI) uses the phase information of MRI, to enhance the contrast of small magnetic susceptibility differences not easily observed in the magnitude images. After filtering, the phase is mapped to values from 0 to 1 by either using positive, negative or triangular windows. Unfortunately, a single-side window is sensitive to the orientation, with respect to the main magnetic field, of the object that produces the phase difference, and the triangular window tends to overestimate the size of the object. In this work, we propose the use of a sigmoid-type window to enhance the contrast of SWI independently of the orientation of the object, as long as it produces a phase change with respect to the surrounding tissue.