Effects of Semaglutide on Intracranial Blood Flow and Brain-Barrier Permeability in Type-2 Diabetes

The investigators preliminary data showed that T2D had significantly reduced total number of distal branches as assessed using the investigators quantitative magnetic resonance angiography (MRA) feature measurement method (iCafe) than non-T2D. This reduction represents a decrease in intracranial blood flow condition and can be an indication for ischemia. Clinical trial showed that semaglutide reduces stroke incidence in T2D. The investigators are conducting a randomized, double blind and placebo-controlled study to investigate the biological basis of the observed stroke reduction with semaglutide by demonstrating semaglutide can improve intracranial blood flow condition and reduce bloodbrain barrier (BBB) permeability. The investigators working hypothesis is that it is known that semaglutide has beneficial effects on T2D, therefore, it improves endothelial function for a better cerebral flow condition. However, semaglutide may also improve cerebral flow independently from glucose lowering. Together, the improved cerebral flow condition results in stroke reduction. In order to investigate the independent effects of semaglutide on intracranial blood flow condition and BBB permeability, the investigators will have a designated diabetes care specialist unblinded to the study randomization to carry out glucose management to achieve HbA1C\<7.5% for both treatment groups.