Examining Salt Appetite in Haemodialysis Patients Using Functional Magnetic Resonance Imaging

HeMSA Study Phase 2 Up to 20 male, haemodialysis patient who have average %IDWG >4% will be recruited with the target, to proceed to scanning, of 14 patients. Following consent the patients will complete questionnaires (including Salt intake questionnaire - DSQ (Gkza and Davenport, 2017), Edinburgh handedness questionnaire (Oldfield, 1971), MRI checklist) and undergo salt taste preference and threshold testing during a 1 hour session prior to dialysis. The purpose of this visit is to establish the tasteless solution and 2 soup salt concentrations to be used in the salt taste fMRI paradigm, obtain baseline data regarding estimate of salt intake and ensure MRI is safe for this patient.

Patients will then attend 2 MRI scanning visits at the Hammersmith Hospital Imperial Campus, one the morning immediately before haemodialysis and one the morning after haemodialysis. Prior to the MRI session, at the Imperial College Clinical Research Facility, the patient will undergo various clinical assessments and have venous blood samples taken. The MRI will be undertaken at the Imperial College Clinical Imaging Facility using a Siemens 3T Verio scanner. During the scan subjects will taste, via a taste delivery system, aliquots of tasteless solution, sucralose, and 2 soup with different concentrations of salt. Solutions will be delivered in a block design.

HeMSA Study Phase 3 3 groups (healthy controls, haemodialysis (HD) patients with %IDWG <4%, haemodialysis patients with %IDWG >4% - patients froms phase 2 will contribute to the latter group) Protocol will follow that for HeMSA Phase 2. Healthy controls will also have 2 study visits at a similar period apart to the HD participants.