RF coils design for small animal MRI lung imaging at 3T using hyperpolarized 129Xe and inert fluorinated gases

摘要

This thesis described the investigation, construction and testing of two sets of RF coils for their applications in novel lung MRI imaging techniques.In the first part of the thesis, a quadrature-driven birdcage coil for rat lung MRI using inert fluorinated gases was developed. Methods for coil tuning and impedance matching were presented and discussed. The sensitivity improvement resulted from a quadrature-driven mode was quantitatively measured, and compared to the linear reference. A dual-angle method (DAM) was studied and implemented to quantitatively measure the B1 field homogeneity, and a B1 field map was generated at the center of the coil. In vivo rat lung imaging experiments were conducted using the constructed coil, and the multi-slice images acquired from the rat lung were presented.In the second part of the thesis, a 1H-129Xe double-birdcage coil for rat lung MRI using hyperpolarized 129Xe gas was developed. The Q factors of each coil was measured and compared before and after the double-birdcage structure was formed. The coupling between the two coils was tested, and a geometrical decoupling method was implemented and optimized. Imaging scans using thermal xenon phantom and saline syringe phantom were conducted with image registration post-processing performed, and the dual-frequency scan ability of the developed coil was verified and evaluated.