Fig. 4.

Distribution of the Gd-tracer over time in each representative region for brain parenchyma. (b) In sections of the olfactory bulb, cerebral cortex, hippocampus, and cerebellum, subtraction images (generated by subtracting the signal ratio maps of the WT group from those of the KO group and converting them into color maps) are shown. Cross-sectional references are indicated by orange dashed lines (a). The KO group showed lower Gd-tracer distribution in the olfactory bulb, ventral and lateral cerebral cortices, hippocampus, and dorsal cerebellum than the WT group (arrowheads). CSF, cerebrospinal fluid; Gd, gadolinium-based contrast agents; KO, aquaporin 4 knockout; WT, wild type.