12 patients received standard (SHD) and cooled (CHD) haemodialysis in a randomized cross-over study. Participants underwent serial cardiac and brain multiparametric MRI before, during and after dialysis. Cerebral blood flow velocities fell significantly during dialysis (carotid artery -19±2%, p<0.001; basilar artery -16±3%, p=0.004). Cardiac index and stroke volume index fell significantly during dialysis (-29±2% and -32±2%, both p<0.001). After two weeks of CHD, pre-dialysis left ventricle (LV) myocardial T1 and wall mass (WM) were lower compared to SHD (T1: 1266(37)ms vs. 1311±18ms, p=0.02; LV WM: 128±12g vs. 137±12g, p=0.003), indicating reduced myocardial tissue oedema with CHD.