Optimization of Quantitative Magnetic Susceptibility Mapping in Brain Regions with Field Inhomogeneity

  • 吳 世偉

Student thesis: Master's Thesis


In MR imaging some regions of the brain are affected by the field inhomogeneity especially around the air-filled cavities e g nasal cavity which can lead to the result of signal loss Therefore many methods are proposed to compensate for the artifacts from signal loss and achieve the better quality of MR images In this study a novel method to compensate for the artifact affected by signal loss is proposed and the result of our method effectively corrected signal loss First we calculate the echo shifts by the k-space energy spectrum analysis (KESA) for our optimization procedure Then the result of the optimization procedure is implemented by applying additional gradients along z-direction (i e z-shim) Moreover we investigate the influence of signal loss and the result of the signal recovery on Quantitative Susceptibility Mapping (QSM) which potentially plays an important role of neuronal disease in recent studies In addition the algorithm we proposed is efficient only takes around 90s to compute the entire processing on line Therefore it is concluded that the new method can effectively restore susceptibility signal loss and improve the quality of QSM with short computation time that provides a great potential for clinical applications
Date of Award2016 Jan 30
Original languageEnglish
SupervisorMing-Long Wu (Supervisor)

Cite this