Phase-based Regional Oxygen Metabolism (PROM) at 3T and feasibility at 7T

Introduction: The cerebral metabolic rate of oxygen (CMRO2) is an important indicator for brain function and disease, including stroke and tumor. CMRO2 can be quantified from measurements of venous oxygen saturation (Yv) and cerebral blood flow (CBF) in cerebral veins. Bulk susceptibility measurements based on gradient-echo phase maps have been used to estimate Yv in vivo at 3T [1]. Challenges of this technique include partial volume effects, phase wrapping, and background susceptibility gradients. Here we quantify CMRO2 by independently measuring Yv and CBF at 3T using MR susceptometry and arterial spin labeling (ASL). We also demonstrate feasibility of quantifying Yv at 7T, which offers higher-resolution analysis of vessels of interest.