Developing and Optimising MRI Tissue Electrical Conductivity Mapping Methods for Structural and Functional Neuroimaging

1) Brief description of the context of the research including potential impact

MRI is indispensable in the diagnosis of neurodegenerative diseases. These are poorly understood while their prevalence and socio-economic burden continue to rise. Structural and functional Magnetic Resonance Imaging (MRI) can provide biomarkers for early diagnosis and potential therapeutic intervention in neurodegenerative diseases. The vision for this research is to optimise MRI methods for simultaneous structural and functional mapping of tissue electrical conductivity as MRI electrical properties tomography (EPT) can distinguish between brain tumour types and shows promise for revealing changes in brain tissue microstructure and ion content in neurodegenerative diseases such as epilepsy and Alzheimer's disease (AD).
The conductivity mapping (CM) techniques developed in this research will allow a rich set of novel, multimodal MRI contrasts to be obtained from a single, efficient scan. This will allow development of new combined structural and functional biomarkers based on tissue conductivity (in addition to tissue magnetic susceptibility) for early diagnosis of AD and other diseases

2) Aims and Objectives

The aim of this project is to develop and optimise MRI acquisition and CM processing methods to provide simultaneous structural and functional brain tissue conductivity maps from a specially designed MRI pulse sequence that can also be used for quantitative magnetic susceptibility mapping (QSM).

The specific objectives are to:
- Design and build a phantom (MRI test object) with several compartments with tissue equivalent conductivities
- Develop an accurate CM method for multiple echo echo-planar imaging (ME-EPI) data acquired in phantoms
- Develop and optimise structural CM techniques for ME-EPI data acquired in healthy volunteers
- Develop and test image processing techniques for resting-state functional CM
- Develop and test physiological noise removal methods for functional CM

The optimisation of MRI acquisition pulse sequences and CM algorithms will be carried out in both phantoms and healthy volunteers. The student will work primarily at the 3 Tesla Prisma MRI system at the National Hospital for Neurology and Neurosurgery. The CM technique we propose is based on the phase (offset) of the complex MRI signal so the phase time-evolution can be used for QSM and the magnitude signal (used for conventional imaging) is still available and can be utilised for standard T2*-weighted imaging and standard functional MRI with no extra scan time cost.

3) Novelty of Research Methodology

The student will develop CM techniques optimised for both structural and functional conductivity mapping. EPI-based CM is novel. It has not been optimised or applied for structural neuroimaging. There are no publications on functional CM or resting-state functional CM which will be enabled by the rapid MRI acquisition sequences and CM algorithms developed as part of this research programme.

4) Alignment to EPSRC's strategies and research areas

This research is most closely aligned with EPSRC's healthcare technologies theme as it aims to accelerate research to healthcare applications. The specific research area pertaining to this research is Medical Imaging. The research may also involve artificial intelligence technologies if deep learning is developed and employed for conductivity mapping.

5) Any companies or collaborators involved

No companies or external collaborators are currently involved in the research.

The critical mass of scientists and engineers that i4health will produce will ensure the UK's continued standing as a world-leader in medical imaging and healthcare technology research. In addition to continued academic excellence, they will further support a future culture of industry and entrepreneurship in healthcare technologies driven by highly trained engineers with deep understanding of the key factors involved in delivering effective translatable and marketable technology. They will achieve this through high quality engineering and imaging science, a broad view of other relevant technological areas, the ability to pinpoint clinical gaps and needs, consideration of clinical user requirements, and patient considerations. Our graduates will provide the drive, determination and enthusiasm to build future UK industry in this vital area via start-ups and spin-outs adding to the burgeoning community of healthcare-related SMEs in London and the rest of the UK. The training in entrepreneurship, coupled with the vibrant environment we are developing for this topic via unique linkage of Engineering and Medicine at UCL, is specifically designed to foster such outcomes. These same innovative leaders will bolster the UK's presence in medical multinationals - pharmaceutical companies, scanner manufacturers, etc. - and ensure the UK's competitiveness as a location for future R&D and medical engineering. They will also provide an invaluable source of expertise for the future NHS and other healthcare-delivery services enabling rapid translation and uptake of the latest imaging and healthcare technologies at the clinical front line. The ultimate impact will be on people and patients, both in the UK and internationally, who will benefit from the increased knowledge of health and disease, as well as better treatment and healthcare management provided by the future technologies our trainees will produce.

In addition to impact in healthcare research, development, and capability, the CDT will have major impact on the students we will attract and train. We will provide our talented cohorts of students with the skills required to lead academic research in this area, to lead industrial development and to make a significant impact as advocates of the science and engineering of their discipline. The i4health CDT's combination of the highest academic standards of research with excellent in-depth training in core skills will mean that our cohorts of students will be in great demand placing them in a powerful position to sculpt their own careers, have major impact within our discipline, while influencing the international mindset and direction. Strong evidence demonstrates this in our existing cohorts of students through high levels of conference podium talks in the most prestigious venues in our field, conference prizes, high impact publications in both engineering, clinical, and general science journals, as well as post-PhD fellowships and career progression. The content and training innovations we propose in i4health will ensure this continues and expands over the next decade.