Exploring Human MRI Radiofrequency Body Arrays at 14 Tesla

• Applicant: Dr.-Ing. Thomas Fiedler
• Subject Area: Medical Physics, Biomedical Technology ; Communication Technology and Networks, High-Frequency Technology and Photonic Systems, Signal Processing and Machine Learning for Information Technology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 548207329

Since the introduction of magnetic resonance imaging (MRI) for medical imaging, there has been an ongoing trend towards higher magnetic field strength to increase the signal-to-noise and contrast-to-noise ratio, with the next step going to a field strength of 14 Tesla (T). Several sites have submitted or are preparing to submit research proposals to establish a 14 T MRI. Funding for the first 14 T human MRI has recently been approved in the Netherlands (Dutch National 14 Tesla MRI Initiative in Medical Science, DYNAMIC). The system is currently expected to be operational in 2028.The project of this application is aimed at investigating and developing RF transmit antenna arrays for human body imaging applications at 14 T MRI (596 MHz).This project proposal, which is supported by project partners from the Dutch 14 T consortium, will contribute the development of RF transmit antenna arrays for body imaging. As there is no 14 T MRI to date, a simulation-based study will be performed in this initial project to design a body array based on developed technology for body imaging at lower field strength and translate methods to the resonance frequency at 14 T.The first step in this project is to establish a basic framework for antenna simulations at the Larmor frequency of 14 T (~596 MHz) and will focus on mesh resolution, anatomical body models and the MR environment. The second step starts with a microstrip antenna element, which has been shown high performance at 7 T and will be optimized for the requirements at 14 T in homogeneous phantoms. Targets in the antenna development are defined to be a high SAR efficiency in the center of a body-sized phantom and low inter-element coupling. Finally, the developed antenna geometry will be investigated in multi-channel array configurations with anatomical body models regarding imaging performance, realistic constraints for RF power, and RF exposure. Optimizations will be performed to homogenize the transmit field in different ROIs. The evaluation will provide information about the necessary number of elements and the position in respect to the human body.The timeline of this proposal is designed to present results in time to pursue experimental validation when the 14 T-system in the Netherlands is operational. Already during the project phase, the results will provide essential information about the hardware requirements (required number of transmit channels to optimize the RF field and needed power of the RF amplifiers), which can be considered during the implementation phase.

• DFG Programme: Research Grants
• International Connection: Netherlands
• Cooperation Partners: Professor Dr. Dennis Klomp; Professor Dr. Andrew Webb