Development Of High-field Magnetic Resonance Imaging Pulse Sequences

Development of pulse sequences plays an important role in the research of magnetic resonance imaging(MRI) control system. It provides a feasible tool for the evaluation of functions and performance of the MRI control system, and also determines the appli-cation range of the whole MRI system. This work realize conventional MRI sequences including GRE,SE and FSE on a self-developed high-field MRI control system and on this basis,UTE pulse sequence has also been developed.1. Theoretical aspects of MRI has been reviewed, the basic knowledge, which is necessary for this work has also been illustrated.2. Technical and practical considerations for realization of the conventional MRI pulse sequences(GRE,SE,FSE) has been summarized and analyzed. Further, we realize these pulse sequences on self-developed MRI control system, proving that the functions and performance of this control system can meet the basic requirements of MRI.3. Make an exhaustive research about UTE, confirm the accuracy of 3D gridding algorithm we wrote in MATLAB and analyze the artifact of UTE pulse sequence by simulation methods, and develop UTE method on self-developed MRI control system.4. Considering the k-space trajectory errors in UTE, a method for k-space trajectory correction has been proposed and realized on Bruker 4.7T MRI system. The results show it can evidently calibrate the back effect of trajectory errors so as to reduce the time needed for UTE imaging.