Table 2. Mean volumes (mL) and volume ratios (%) of CSF and brain parenchyma.

	iNPH (52)	sNPH (15)	Control (31)	P1	P2	P3
Total intracranial spaces	1517 ± 156	1467 ± 147	1487 ± 138	0.310	0.369	0.639
Brain parenchyma	1096 ± 119 (72.4%)	1177 ± 134 (80.3%)	1154 ± 147 (77.5%)	0.061	0.017	0.746
Total CSF	420.4 ± 84.7 (27.6%)	290.0 ± 85.2 (19.7%)	333.1 ± 94.0 (22.5%)	<0.001	<0.001	0.075
Total ventricles	160.8 ± 45.2 (10.6%)	121.4 ± 26.8 (8.2%)	61.3 ± 31.9 (4.2%)	0.002	<0.001	<0.001
Bilateral ventricles	152.9 ± 41.7	112.2 ± 26.7	52.1 ± 26.4	<0.001	<0.001	<0.001
Third ventricle	5.3 ± 1.5	5.2 ± 1.2	3.5 ± 1.3	0.982	<0.001	<0.001
Fourth ventricle	4.1 ± 2.0	4.5 ± 1.1	2.8 ± 1.5	0.181	0.002	<0.001
Total subarachnoid spaces	259.6 ± 71.5 (17.1%)	168.4 ± 72.3 (11.5%)	271.7 ± 85.7 (18.3%)	<0.001	0.569	<0.001
Convexity subarachnoid space	76.4 ± 35.4	73.0 ± 35.9	125.8 ± 54.8	0.758	<0.001	<0.001
Basal cistern and Sylvian fissure	120.4 ± 32.7	51.6 ± 35.0	90.7 ± 34.0	<0.001	<0.001	0.001
Posterior fossa	62.8 ± 17.7	43.9 ± 10.2	55.2 ± 19.7	<0.001	0.057	0.038

P1; probability value of iNPH vs. sNPH for the Mann-Whitney-Wilcoxon test.

P2; probability value of iNPH vs. control for the Mann-Whitney-Wilcoxon test.

P3; probability value of sNPH vs. control for the Mann-Whitney-Wilcoxon test.