Audrey P. Fan1, 2, Berkin Bilgic1, 2, Keith A. Heberlein2, Bruce R. Rosen2, 3, Elfar Adalsteinsson1, 2
1Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States; 2Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States; 3Harvard Medical School, Boston, MA, United States
We substantially improved the phase-based regional oxygen metabolism (PROM) MRI method to quantify absolute cerebral metabolic rate of oxygen (CMRO2) in vivo across the cortex. Quantitative susceptibility maps were reconstructed from high-resolution 3D phase images using L1-regularization, from which venous oxygen saturation (Yv) was quantified. Improved removal of background fields in the measured phase allowed for less than 5% error Yv even in vessels perpendicular to B0. Yv was averaged for 31 cortical regions per hemisphere after anatomical registration, representing 380% increased coverage from the previous version of PROM. With an additional perfusion map from arterial spin labeling, we measured mean Yv=62.34%, CBF=48.710ml/100g/min, and CMRO2=13432μmol/100g/min across the cortex, which lie in the normal physiological range.