Research Directions

         Parallel imaging, Parallel Excitation/transmit SENSE, new strategies for fast MR imaging, ultrahigh field MR technology, innovative RF coils and coil arrays for ultrahigh field MRI, computational electromagnetics in in-vivo MR, MRI compatibility and safety for implanted devices.

Research Summary

         Magnetic resonance (MR) has been proven to be a robust noninvasive, nonionic imaging modality in biomedical investigations and clinical diagnosis. The major problem of MRI is its long acquisition time and low sensitivity, consequently resulting in limited temporal resolution and spatial resolution. Parallel imaging and ultrahigh field MR(7T and above) are two promising MR methodologies emerged recently which are capable of improving conventional MR performance in temporal resolution and spatial resolution in vivo. My research focuses on development of the parallel imaging technique, ultrahigh field MR, and also integration of the two promising techniques, providing a fast, highly sensitive MR for in vivo biomedical research. The research endeavor involves parallel imaging algorithm, transmit SENSE, parallel excitation, new strategies for high frequency RF coils and coil arrays, electromagnetic problems and computational electromagnetism in in-vivo MR at high fields by using FDTD method and other finite element methods, and applications of the developed techniques to in vivo MR Imaging and spectroscopy. One of such applications is related to the use of the hyperpolarized C-13 MR spectroscopic imaging to study metabolism and pathology in normal and cancerous conditions in humans and experimental animals. With increased capability of temporal resolution and spatial resolution, exploration of DTI with SENSE technique at 7T is also an important research field in our group. Another research component in our group is MRI compatibility and safety of implanted medical devices, making MRI examinations possible to numerous patients with implanted medical devices, such as the pacemaker.

Current Research Grants

1. RF Coils for Parallel MRI/MRS in vivo at High Fields
NIH R01 EB004453

2. Multichannel Dual-tuned Transceiver Techniques for Human Low-Gamma Nuclei MR
NIH R01 EB008699

3. Technique Development for Hyperpolarized C-13 MR Studies
NIH R01 EB007588-03S1

4. Parallel Excitation and Multiple Transceiver Channels for Enhanced Parallel Imaging Capability at 7T
QB3 R1 Research Award

With quantitative capability, magnetic resonance imaging and spectroscopy (MRI/MRS) have become a promising non-invasive imaging modality for biomedical research. This project aims to upgrade our 7T whole body MR system housed in the QB3 with multiple transmit/receive channels. This upgrade will enable the parallel imaging technique for both signal transmit and receive on the 7T system. The multi-channel transceiver is capable of independent amplitude and phase control of RF excitation power. With the multiple channels, parallel imaging techniques can be used to dramatically accelerate the acquisitions (thus increase temporal resolution), improve image SNR, or increase the spatial resolution, performance of transmit SENSE, and RF shimming at the ultrahigh field. The successful outcome of this upgrade will significantly improve the 7T imaging capability in basic and clinical research. The improvement will provide a much powerful, highly sensitive and fast imaging tool and significantly benefits a wide range of biomedical research in a qualitative fashion within the QB3. This research effort could give our 7T MR, a multi-million dollars project, a quantum leap and move imaging capability of QB3 to the forefront of the field. This is not about a local competition or a simple improvement of QB3, but rather about making QB3 a world leader in in-vivo MRI/MRS methodology and its medical, biological and pharmaceutical research applications.

5. Dual-frequency transceiver for detection & quantification of brain tumors using hyperpolarized C-13 and H-1 parallel MR spectroscopic imaging at 7T
NIH/NCRR UCSF-CTSI Grant Number UL1 RR024131-01

The unprecedented sensitivity gain of hyperpolarized 13C MR provides a new hope to study human brain and metabolism by using MR Imaging at 7T. However the major obstacle hindering the implementation of this innovative technique is the design of the required dual-frequency RF transceivers. We propose a translational project using our newly developed microstrip method to develop dual-frequency transceivers for brain tumor detection and quantification by hyperpolarized 13C MR. The technique developed is also applicable for tudying
normal brains and brains with other diseases.