Glioma Oxygenation and vasculature: In the spotlight of MRI

Assessing oxygenation and vasculature in gliomas is important for understanding their physiology and guiding treatment decisions. Oxygenation levels can indicate tumor malignancy and resistance to therapeutic interventions such as radiotherapy. In parallel, vascular evaluation provides insights into the tumor's angiogenesis and proliferative capacity. This thesis advances the use of non-invasive MRI techniques for analyzing oxygenation and vasculature in glioma tumors. To validate MRI findings, targeted biopsies and histopathological examinations were conducted, enabling a comparison of macroscopic MRI results with microscopic histopathological insights.

This thesis utilizes two advanced MRI techniques. The first, quantitative BOLD (Blood Oxygen Level Dependent), measures the Oxygen Extraction Fraction (OEF), which indicates the proportion of oxygen extracted from the blood as it circulates through the brain. A higher OEF suggests areas of increased metabolic activity and potential aggressiveness within the tumor. The second technique, Vessel Size Imaging (VSI), assesses relative cerebral blood volume (rCBV) and microvascular size. rCBV provides insights into the volume of blood within brain tissue and indicates the level of angiogenesis, crucial for tumor growth. Vessel size is crucial because it directly influences the efficiency of blood and oxygen delivery to the tumor. Smaller, more numerous capillaries can enhance oxygen exchange at the cellular level, while larger, irregular vessels may lead to uneven oxygen distribution.