Validation of Constrained qBOLD-Based 3D CMRO2 Mapping With Repeatability Test and Hypercapnic Challenge

In the original qBOLD, it is challenging to separate deoxyhemoglobin’s contribution to R2' from other sources modulating the voxel signal. Further, extracting DBV and Yv from measured R2' is a nontrivial task. It was recently shown that the constrained qBOLD method was able to properly separate the several confounding factors, yielding the expected contrast for both Yv and DBV maps across the entire brain, and, together with a separate measurement of CBF, leading to whole-brain 3D CMRO2 maps within physiologically plausible ranges. Here, we validated the new 3D qBOLD method with respect to repeatability and hypercapnic gas breathing challenges.