CTSI Annual Pilot Awards to Improve the Conduct of Research

An Open Proposal Opportunity

Broadband Multichannel Transmitters for Enhanced Metabolic MR Imaging

Proposal Status: 

1. Rationale

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 It has significantly limited the capability of imaging and restricted its applications to conventionally slow and outdated approaches.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.  

2. Plan

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.

5. Collaborators

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


Interesting project which will dramatically enhance the quantitative imaging capability of our existing high-end MR instrumentation. The project seems doable though I suspect that the anticipated budget is too low for the goals and it would have been nice if the plan included strategies to broaden the number and disciplines of the potential collaborators.

Agree that this doesn't seem like enough to get the project to a working state. Is the plan to build a case for outside funding?

This does sound like a fascinating project. Because it is technical in nature, I am curious as to how the upgraded transmitters would integrate with existing infrastructure, and how scalable the initial investment would be. Would this project generate new costs and/or revenue beyond its development phase?

Thanks so much for taking time to review this project. I agree that the budget is tight. Our goal is to design and construct a lab prototype of the multichannel transmitter system to enable the use of emerging imaging techniques and advance our quantitative imaging capability. Many blocks of the proposed system, including all the circuits, will be made in house by using the fabrication facility provided in Surbeck Lab for Advanced Imaging at UCSF. This would significantly reduce the cost compared with subcontracting the jobs to outside manufactures. Despite a prototype, the system should have the expected performance and should be able to operate with MR imaging systems in Surbeck Lab. I feel that the current budget is reasonable for developing such a prototype although it’s tight. We are trying every effort to reduce the cost and hope to make this development endeavor possible in this lean year. Of course, the proposed budget is certainly not enough to develop a commercial product-like system which would involve a large amount of efforts on production engineering, including intensive mechanical design and fabrication. In terms of broadening the collaborators, since the proposed system is a shared instrumentation, we welcome any faculty members from any disciplines to use it if they think this advanced quantitative MR imaging system is of help to their research. We are also very happy to provide any necessary assistance for performing the imaging experiments. With the success of this project, we would be able to plan larger and more comprehensive projects with an emphasis on performance improvement and preclinical applications of the system for outside funding opportunities. This increased imaging capability enabling advanced imaging technologies would also help to increase the likelihood of success in our routine NIH grant applications. This system will be designed in a PC-control style. Our intention for this design is the easy integration with the existing MR imaging scanners. The multichannel transmitter will be synchronized for MR signal excitation and acquisition by a clock signal generated from MR imaging scanners. Based on our tests, integration with existing MR system should not be a problem for the proposed design. Each channel is well decoupled from others and is highly independent. The number of channels is scalable. Certainly, less channel number would cost less. In the future development, adding more channels is convenient; at least no need to pay more efforts or costs on R&D. Basically this system is maintenance free and will not cause additional costs on its operation beyond its development phase. If needed, a recharge will be setup for use of this system. In this case, revenue can be expected.

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