Quantitative perfusion and oxygenation MRI in the brain

The human brain relies on a continuous supply of oxygen and nutrients delivered through blood circulation. Disruptions in this autoregulatory system can lead to tissue damage and are associated with cognitive decline and various diseases. Magnetic Resonance Imaging (MRI) offers non-invasive quantitative techniques to assess blood flow, oxygen metabolism, and brain tissue integrity, potentially serving as biomarkers for cerebrovascular dysfunction-related pathologies.
This thesis aimed to optimize and evaluate several non-invasive MRI techniques to assess cerebrovascular hemodynamics and oxygen metabolism, advancing their clinical utility. This work investigated the reproducibility of cerebral blood flow (CBF) measurements using arterial spin labeling (ASL) and provided guidelines on when protocols can be compared reliably. It also demonstrated the feasibility of dynamic CBF measurements during a bicycling exercise using ASL. Next, two techniques to estimate venous blood oxygenation were compared, favoring the T2-relaxation-under-spin-tagging (TRUST) sequence over T2-Prepared-Blood-Relaxation-Imaging-with-Inversion-Recovery (T2-TRIR). Chapter 6 and 7 explored cerebrovascular hemodynamics and oxygen metabolism in patients with sickle cell disease and Thalassemia, identifying potential factors contributing to cerebral infarcts and white matter lesions formation. Lastly, this work investigated whether changes in diffusion precede the formation of white matter lesions (WML) in patients with Fabry disease
In conclusion, this thesis demonstrated the feasibility and clinical value of several non-invasive MRI techniques for assessing cerebrovascular health. The findings provide reference points and insights for future research and clinical applications, aiming to improve diagnostic accuracy and treatment strategies for cerebrovascular diseases.