臺灣大學數學系專題演講博士生論文口試
演講者：徐義程
講  題：Mathematical theory and technical designs for magnetization excitation in high field MRI
時  間：2013年6月27日 (星期四) 14:00
地  點：臺灣大學天數館440室
摘  要：This talk aims at developing mathematical theory and providing technical implementations of designing the spatial distribution of magnetization in magnetic resonance imaging (MRI) experiments. While MRI has become a prevailing tools in both clinical diagnosis and neuroimaging studies, one particular challenge of improving the signal-to-noise ratio (SNR) of the MRI data by increasing the main magnetic field strength (B0) is the inhomogeneous flip angle distribution when a volume RF coil is used for RF excitation, which leads to spatially varying contrast and consequently makes diagnosis difficult. While this challenge can be mitigated by spatial selective excitation or parallel transmission excitation, these methods are problematic because 1) the pulse duration may be too long and magnetization relaxation causes the magnetization distribution significantly deviating from the designed distribution, 2) the RF power may be too strong cause specific absorption rate (SAR) concerns, 3) expensive parallel transmission system is required and complicated calibration procedures are needed. I attempt to mitigate the above mentioned challenges by providing new analytical approaches and technical methods.