Broadband Multichannel Transmitters for Enhanced Metabolic MR Imaging
CTSI Annual Pilot Awards to Improve the Conduct of Research
An "Open Proposal" Opportunity
Surbeck Laboratory for advanced imaging at UCSF, is an interdepartmental and interdisciplinary laboratory that provides unique instrumentation, expertise, and infrastructure to enable the faculty, trainees and staff to carry out translational and clinical research utilizing the unique capabilities of high magnetic fields. Research at the Surbeck Lab has resulted in some of the most advanced MR instrumentation and expertise currently available and has been the source of critical technologies and methodologies in multiple areas of non-invasive biomedical research at cellular and molecular scale.
With quantitative capability, magnetic resonance imaging and spectroscopy (MRI/MRS) have become a promising non-invasive imaging modality for biomedical research. This application seeks funding to enhance our quantitative imaging capability through development of broadband multichannel transmitters on the high-end whole body MR imaging systems. Currently our MR systems at Surbeck Lab are equipped with only 1 transmit channel. It has significantly limited the capability of imaging and restricted its applications to conventionally slow and outdated approaches. The proposed development will enable the advanced imaging technologies on our UCSF MR systems and significantly improve our research infrastructure. With the multiple transmitters, parallel imaging techniques with fast selective excitation and B1 shimming can be used to dramatically accelerate the imaging speed, improve imaging sensitivity and reduce sample heating. This will be a shared instrumentation and would significantly benefit a wide range of biomedical research in a qualitative fashion and facilitate translational and clinical research projects within UCSF community. This development could give our quantitative imaging resource a quantum leap and move imaging capability of UCSF to the forefront of the field. This is not about a local competition, but rather about making UCSF a world leader in in-vivo MRI/MRS methodology and its medical, biological and pharmaceutical research applications. This would be an invaluable asset which benefits the whole UCSF community tangibly.
This project will be accomplished via the following three steps.
a) Design and construction of broadband 16-channel transmitter system with capabilities of high transmit power, independent amplitude and phase control, and independent RF pulse waveform generation. This system allows for parallel transmit, B1 field shimming and increased MR sensitivity, consequently resulting in high sensitivity, high temporal resolution, uniform image, and reduced tissue heating; The broadband capability enables multi-nuclear and multi-field-strength MR imaging.
b) Development of user-friendly interface software and integration of the proposed multi-channel broadband transmitters to the GE MR control software, ensuring the compatibility with the GE MR console;
c) Broadband transmitter installation, testing, validation, and safety assessment on 3T and 7T systems.
3. Criteria and metrics for success
The proposed multichannel transmitters will be tested on bench. Each transmitter channel should have a frequency range of 120MHz to 300MHz, a phase range of -200 to 3800. RF power attenuation should be able to control the output from 30dB to 5dB with max 200W output. MR imaging experiments validation will be performed on the 3T and 7T MR imaging systems housed on UCSF Mission bay campus. In MR imaging experiments, the overall B1 field pattern can be controlled by changing RF amplitude and phase of each transmitter channel. Improved MR sensitivity and reduced SAR should be observed.
4. Approximate cost and very brief justification ($10k-max $100k)
We request budget to buy required electronic parts for constructing the proposed multi-channel transmitters, including capacitors, inductors, phase shifters, attenuators, mixers, coaxial cables, RF connectors, and also circuit board manufacturing, etc ($35,000); General lab supplies for constructing and testing the transmitters ($10,000); MR scans for performance validation (10 hours x $500/hr = $5,000); 15% effort of the PI (Xiaoliang Zhang, PhD) who will be responsible for the administration and direction of the project, also aid in designing, constructing, testing, and validating the proposed transmitters, help in equipment installation and hardware/software integration, and assist in the data analysis and interpretation ($21,750). 30% effort of an engineer (Yong Pang, PhD) ($13,500). This person will design the transmitter circuits and required software for user-friendly interface to control the transmitters; Total direct costs requested: $85,250.
Collaborators of our research lab include Daniel Vigneron, PhD; Sarah Nelson, PhD; Sharmila Majundar, PhD; Christopher Hess, MD; Xiaojuan Li, PhD; David Wilson, MD; Duan Xu, PhD; Orit Glenn, MD; John Kurhanewicz, PhD; Jin Liu, PhD; Sabrina Ronen, PhD, Pedar Larson, PhD; Roland Kruger, PhD