Real-time MRI to study processes of chewing and swallowing

Background
Dysphagia is a common condition, with the most severe and complicated cases following on from oral malignancies (>6,000 new cases each year in the UK alone), radiotherapy (applied to the head & neck region), and auto-immune conditions. It has a major, life-long negative impact on a patient’s quality of life. For example, xerostomia causes difficulties with eating, drinking, speaking and breathing. Dysphagia often leads to social isolation, malnutrition and high rates of depression/suicide. Clearly, there are serious unmet clinical needs. Aftercare could be significantly improved through a better understanding of the processes of chewing/swallowing, related to the rheology of foods (hydrocolloids) and bolus formation. This, in turn, requires experimental methods to observe these processes in situ, characterising the relevant properties of different food textures to inform clinical care plans. We recently demonstrated that real-time MRI methods are a suitable approach in this context. Such data can aid clinicians in improving surgical planning, post-operative short/long term rehabilitation and monitoring. MRI ‘videos’ can find wide impact, being straightforward to implement on existing clinical MRI scanners. These preliminary investigations now need to be fully developed.

Objectives
The overarching aim for this project is the development of a robust prototype protocol for the establishment of real-time MRI methods in clinical practice in oral & maxillofacial surgery. There are several milestone objectives en route: • Mapping of a range of food rheologies and textures in terms of MRI parameters; • Choosing suitable (organic and inorganic) contrast agents (e.g. paramagnetic ion complexes, superparamagnetic magnetite particles, natural agents such as pineapple) where required; • Establishing a 3D/4D real-time MRI data reconstruction and representation; • Obtaining feedback from surgeons, patients & carers about image representations.

Experimental Approach
Our real-time MRI approach uses radial FLASH based MR sequences; some further evaluation and optimisation of various technical aspects is necessary. We can currently achieve 70 image frames per second (fps). With further development, this could extend to ~200 fps. Real-time MRI experiments can be carried out on a dedicated SIEMENS 3T PRISMA MRI research scanner within the York Neuroimaging Centre, with healthy volunteers and patients (ethics approved). Development of 3D/4D image reconstruction and representation can mainly rely on our existing real-time MRI data sets. The main tool for code development will be MATLAB. It is foreseeable that the computational work will use the Viking high-performance computation cluster. Mapping of food rheologies and textures in terms of relevant MRI descriptors requires the measurement of T1/T2/T2* relaxation characteristics of a wide range of foods and lubricants. Relaxometry measurements can be carried out on existing NMR/MRI systems within the Centre for Hyperpolarised MR. Depending on these relaxation measurements, the role of contrast agents needs to be established, where necessary. Novelty real-time MRI was first implemented in 2010 and has since improved cardiac monitoring, but has not found previous clinical application in the brain/head.

Novelty here is the development and application of the method for in-depth examinations of the mechanics of swallowing/speaking/breathing. A fully clinically co-created real-time MRI protocol, including 3D/4D data representations, will make a transformative contribution. There is enormous potential for major improvements in surgical planning, patient information, rehabilitation after treatment, early detection of adverse radiotherapy effects and long-term monitoring of tumour recurrence.

Training
The nature of the project is cross-disciplinary and thus provides opportunities (and need) to learn about: • complex image reconstruction methods; • hydrocolloid (food) rheologies; • physico-chemical aspects of NMR relaxation; • experimental NMR and MRI data acquisition; • project planning and methodology evaluation; • communicating about scientific matters with clinicians and lay people as a pathway to impact.

All Chemistry research students have access to our innovative Doctoral Training in Chemistry (iDTC): cohort-based training to support the development of scientific, transferable and employability skills: https://www.york.ac.uk/chemistry/postgraduate/idtc/

The Department of Chemistry holds an Athena SWAN Gold Award and is committed to supporting equality and diversity for all staff and students. The Department strives to provide a working environment which allows all staff and students to contribute fully, to flourish, and to excel: https://www.york.ac.uk/chemistry/ed/. This PhD project is available to study full-time or part-time (50%).

This PhD will formally start on 1 October 2020. Induction activities will start on 28 September.