Fig. 5.

(A) Demonstration of single voxel time course of rat brain H₂¹⁷O signal and change taken from three-dimensional (3D) in vivo ¹⁷O MRSI measured before, during and after two inhalations of ¹⁷O₂ for repeated CMRO₂ and CBF imaging measurements. Adapted from the reference of Zhu et. al. [53]. (B) 3D functional CMRO₂ activation maps (middle column) obtained from cat visual cortex showing relative increases of CMRO₂ elevated by visual stimulation from a representative animal. The corresponding fMRI BOLD maps and anatomic brain images are also shown in the right and left column, respectively. (C) Summary (top panel) of baseline and activated CMRO₂ in the visual cortex from five cats (repeated two studies from Cat 5), and the dependence between the baseline CMRO₂ level and evoked CMRO₂ percent change, indicating a negative correlation. Adapted from the reference of Zhu et. al. [54].