Relationships Among Multimodal MRI Markers of Neurovascular Integrity and Fluid Transport in Ageing and Neurodegenerative Disease: A System-Level Investigation of Brain Health

As we age, multiple systems that support brain function gradually change, including those that regulate blood flow and the movement of fluid that removes waste. These changes can increase vulnerability to conditions such as dementia and small vessel disease, which affect memory and thinking and are among the most prevalent diseases in older adulthood. This thesis used brain imaging to examine how these systems interact, analysing multiple measures together rather than in isolation. By combining information across different types of brain scans, blood markers, and health measures, this work showed that groups of related measures can provide nuanced insight into brain changes associated with ageing and dementia. Viewing brain health as the product of interconnected systems may improve early detection and monitoring of age-related brain disease.