FIGURE 1.

Co-registered rat head images with 5mm scale bar: (A), ¹H FLASH structural image of the coronal rat head anatomy. Regions of interest (ROI) for brain tissue (green) are highlighted for each hemisphere and laterally left and right for muscle tissue (i.e. predominantly temporalis lateralis; red); (B), in vivo H₂¹⁷O image acquired within 30 s shortly before the onset of a ¹⁷O₂ inhalation, with intensity highlighting (2× brighter) of the ROIs for better visualization; and (C), very high resolution H₂¹⁷O enriched post-mortem image acquired after repeated inhalations with ROIs marked as in (A). All slices cover the same FOV at the Z-position of the Bregma. Visualization of brain and muscle (dotted line) based on proton images (A). ¹⁷O images in (B,C) are zero-filled (×2) in the spatial dimensions.