Quantitative Susceptibility Mapping

Magnetic susceptibility is an intrinsic tissue property that characterizes the perturbation of the magnetic field by the presence of the matter. Biological tissues exhibit differ magnetic susceptibility. For example, iron has positive magnetic susceptibility value while myelin has negative susceptibility value. Quantitative susceptibility mapping (QSM) is a method that reconstructs magnet susceptibility distribution from phase image of gradient echo sequence. The processing of QSM includes three steps: phase unwrapping, background field removal, and dipole deconvolution. Our research team is applying QSM to study a number of diseases including abnormal iron content in the brain of beta-thalassemia patients and sickle cell disease patients.