Table 4. Descriptive summary of findings presented in the current study.

Bold italic font highlights the regions of the largest differences found between KO and WT animals, by means of 3 MRI and 5 physiological and histological assessment methods applied.

Magnetic resonance imaging in vivo
Measurement		General findings in KO compared to WT	Region of largest difference
non-invasive	3D cisternography	- 5–10% larger brain volumes - 22–29% smaller CSF space / brain volume ratio	ventricular space, 3rd ventricle
	2D diffusion-weighted imaging	5–6% higher ADC and D	(difference present for average and in all diffusion directions) - thalamus, hindbrain, periaqueductal gray regions, auditory cortex and hippocampus
		Higher Fp and Fp × D* only in the 3rd ventricle
invasive	Dynamic CSF tracer imaging via cisterna magna`	reduced parenchymal tracer influx and evacuation	- influx: cortical ROI, hippocampus - efflux: superior sagittal sinus
Physiological and histological measurements
Measurement		General findings in KO compared to WT	Region of largest difference
ex vivo and histology	Brain water content	~6% larger brain water content
	AQP4 expression	(only WT) heterogenous AQP4 expression in the brain	largest expression in the thalamus, hippocampus, habenula
	Vascular density	similar vascular density to WT	trend for larger vascular density in the thalamus and olfactory area
in vivo	CSF production	similar CSF production to WT
	Real-time ionophoresis TMA	ISF space volume larger