Article Figures & Data
Figures
- FIG 1.
Schema explaining OSS: θ(n) is the angle between
and in the nth phase (n)
Where indicates a vector of TAWSS, and indicates a vector of WSS. - FIG 2.
Oscillation of WSS due to bidirectional CSF flow through the cerebral aqueduct. The numbers 1, 2, and 3 demonstrate temporal changes of the reciprocating CSF motion during 1 cardiac cycle in a 77-year-old man diagnosed with iNPH. The colored path lines (lower figures) show the flow as a moving trajectory of the virtual particle through the middle part of the cerebral aqueduct in 1 heartbeat. The color and length of 3D streamlines (upper figures) indicate the flow velocity as pink for fast and blue for slow. The sampling interval of streamlines and path lines was set at 0.2 mm after the trilinear interpolation. The arrows indicate the WSS vector produced by the flow parallel to the wall surface. The size and direction of the arrows indicate the magnitude and direction of the WSS vector. Temporal changes of the WSS vector at the dorsal region (yellow arrows) were larger than those at the ventral region (white arrows).
- FIG 3.
Distributions and fluctuations of shear stress parameters per heartbeat in iNPH. The colored surfaces in the ventricles show the distribution of WSS magnitude (A) and OSI (B) in the same patient with iNPH, as shown in Fig 2. Red indicates high and blue indicates low. Line-graphs C and D show chronologic changes of WSS magnitude and OSS at the dorsal region of the foramen magnum (ROI 2, yellow) and dorsal (ROI 3, red) and ventral (ROI 4, blue) regions of the cerebral aqueduct in 1 cardiac cycle. Considering the shear stress direction, these changes were completely different.
- FIG 4.
Boxplots for the amplitude of OSS and TAWSS at the dorsal and ventral regions of the cerebral aqueduct among 3 groups. A, Distribution of the OSS amplitude at the dorsal region of the cerebral aqueduct. B, Distribution of the TAWSS at the dorsal region of the cerebral aqueduct. C, Distribution of the OSS amplitude at the ventral region of the cerebral aqueduct. D, Distribution of the TAWSS at the ventral region of the cerebral aqueduct.
Tables
iNPH Only iNPH with AD Control P Value Total number 41 23 9 Male/female 28:13 13:10 4:5 .332 Age (yr) 78.2 [SD, 6.62] 79.8 [SD, 5.83] 75.7 [SD, 5.70] .207 Anteroposterior diameter (mm) Foramen of Magendie 5.72 [SD, 1.77] 5.88 [SD, 2.04] 2.02 [SD, 0.44] <.001 Lower end of cerebral aqueduct 4.44 [SD, 0.87] 4.25 [SD, 1.41] 2.23 [SD, 0.70] <.001 Upper end of cerebral aqueduct 3.65 [SD, 0.66] 3.45 [SD, 0.73] 2.30 [SD, 0.54] <.001 Midbrain 8.56 [SD, 0.88] 8.43 [SD, 0.92] 9.32 [SD, 1.57] .230 Stroke volume (μL/heartbeat) Foramen of Magendie 32.9 [SD, 22.6] 37.4 [SD, 37.6] 21.1 [SD, 11.7] .448 Lower end of cerebral aqueduct 37.6 [SD, 28.9] 39.6 [SD, 43.7] 17.8 [SD, 13.0] .083 Upper end of cerebral aqueduct 49.0 [SD, 33.3] 52.6 [SD, 32.5] 18.9 [SD, 10.5] .002 Foramina of Monro 96.5 [SD, 41.0] 97.8 [SD, 39.1] 62.8 [SD, 44.6] .042 a Data are means. P value is from the Kruskal-Wallis rank sum test.
All (n = 73) iNPH Only (n = 41) iNPH with AD (n = 23) Control (n = 9) P1 P2 P3 Dorsal region of the cerebral aqueduct OSS amplitude 52.5 [SD, 33.9] 59.7 [SD, 34.1] 52.9 [SD, 32.2] 19.8 [SD, 13.3] .483 <.001 .004 Maximum OSS 35.9 [SD, 16.0] 38.7 [SD, 15.5] 37.3 [SD, 16.1] 19.7 [SD, 6.3] .566 <.001 .002 Minimum OSS –16.7 [SD, 19.8] –21.0 [SD, 20.2] –15.6 [SD, 18.9] –0.1 [SD, 9.6] .277 .001 .043 TAWSS 18.2 [SD, 8.9] 19.7 [SD, 8.7] 18.8 [SD, 9.3] 9.9 [SD, 2.2] .678 <.001 .008 OSI 0.21 [SD, 0.13] 0.24 [SD, 0.12] 0.19 [SD, 0.14] 0.16 [SD, 0.11] .234 .077 .614 Ventral region of the cerebral aqueduct OSS amplitude 27.2 [SD, 28.4] 36.0 [SD, 32.2] 18.1 [SD, 19.8] 11.9 [SD, 11.1] .022 .020 .363 Maximum OSS 23.6 [SD, 15.9] 28.8 [SD, 17.9] 18.2 [SD, 10.9] 14.2 [SD, 6.4] .017 .011 .246 Minimum OSS –3.6 [SD, 13.9] –7.1 [SD, 15.9] 0.14 [SD, 10.1] 2.3 [SD, 7.5] .080 .091 .592 TAWSS 12.2 [SD, 7.1] 14.3 [SD, 8.1] 10.1 [SD, 4.9] 8.1 [SD, 2.7] .038 .020 .458 OSI 0.13 [SD, 0.15] 0.15 [SD, 0.15] 0.10 [SD, 0.14] 0.11 [SD, 0.15] .114 .355 .910 ↵a P1 indicates probability value of iNPH only versus iNPH with AD by the Wilcoxon rank sum test; P2, probability value of iNPH only versus controls by the Wilcoxon rank sum test; and P3, probability value of iNPH with AD versus controls by the Wilcoxon rank sum test.
- Table 3:
Relationships with anterior-posterior diameter by the Pearson correlation coefficient (95% confidence intervals)
Foramen of Magendie Lower End of Cerebral Aqueduct Upper End of Cerebral Aqueduct Midbrain Dorsal region of the cerebral aqueduct OSS amplitude 0.55 (0.36–0.69) 0.47 (0.26–0.63) 0.28 (0.05–0.48) NS Maximum OSS 0.53 (0.34–0.68) 0.41 (0.20–0.59) NS NS Minimum OSS –0.51 (–0.66 to –0.31) –0.46 (–0.63 to –0.26) –0.32 (–0.51 to –0.10) NS TAWSS 0.56 (0.37–0.70) 0.40 (0.18–0.58) NS NS OSI NS NS NS NS Ventral region of the cerebral aqueduct OSS amplitude NS 0.27 (0.04–0.47) NS NS Maximum OSS NS 0.31 (0.08–0.50) NS NS Minimum OSS NS NS NS NS TAWSS 0.26 (0.04–0.47) 0.33 (0.10–0.52) NS NS OSI NS NS NS NS Note:—NS indicates not significant (P ≥ .05) by the Pearson correlation analysis.
- Table 4:
Relationships with stroke volume by the Pearson correlation coefficient (95% confidence intervals)
Foramen of Magendie Lower End of Cerebral Aqueduct Upper End of Cerebral Aqueduct Foramina of Monro Dorsal region of the cerebral aqueduct OSS amplitude 0.48 (0.28–0.64) 0.53 (0.34–0.68) 0.63 (0.47–0.76) NS Maximum OSS 0.50 (0.31–0.66) 0.56 (0.37–0.70) 0.66 (0.50–0.77) NS Minimum OSS –0.41 (–0.59 to –0.20) –0.46 (–0.63 to –0.26) –0.55 (–0.70 to –0.37) NS TAWSS 0.43 (0.22–0.60) 0.53 (0.34–0.68) 0.73 (0.60–0.82) NS OSI NS NS NS NS Ventral region of the cerebral aqueduct OSS amplitude NS 0.30 (0.07–0.50) 0.25 (0.02–0.46) NS Maximum OSS NS 0.32 (0.10–0.52) 0.29 (0.07–0.49) NS Minimum OSS NS –0.24 (–0.45 to –0.01) NS NS TAWSS NS 0.37 (0.15–0.55) 0.34 (0.12–0.53) NS OSI NS NS NS NS Note:—NS indicates not significant (P ≥ .05) by the Pearson correlation analysis.
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