Legend of waveform feature points (Fig. 1) in the corresponding compartments.

<p>Legend of waveform feature points (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037502#pone-0037502-g001" target="_blank">Fig. 1</a>) in the corresponding compartments.</p

Mean magnitude and phase of transfer function (bold line) and standard deviation (gray shading) from arterial input to cervical spinal cerebrospinal fluid (CSF) flow, A and B, at the level of C3–C4, and to aqueductal CSF flow, C and D, of elderly (gray line) and young (black line) groups as a function of frequencies.

<p>Significant differences of the magnitude and phase as detected by the Mann-Whitney test are depicted at the respective frequency. At 2 Hz the phases of the arterial-to-aqueductal flows hardly overlap <b>D</b>, resulting in an asymptotic 2-tailed p-value of .</p

Juxtaposed frequency components (Hz) of flow in the elderly (gray, left) and young groups (black, right) illustrated using Boxplots.

<p>The upper and lower edges of each box represent the 25th and 75th percentiles, respectively. The center line represents the median and the whiskers extend to the most extreme data points not considered outliers, which are plotted individually (+). In each subfigure, frequency components are separated by dotted lines. In <b>A</b>, the first to the 10th frequency components of the combined flow rates in the carotid and the vertebral arteries are plotted, in <b>B</b>, the first to the seventh frequency components of the cerebrospinal fluid (CSF) flow rate in the cervical spinal canal at the level of C3–C4 and in <b>C</b>, the first to the 5th frequency components of CSF flow rate in the aqueduct. Curly brackets indicate significant differences of the respective frequency component's magnitudes detected with the Mann-Whitney test. Note that the fourth frequency components of the arterial flows <b>A</b> hardly overlap, thus the corresponding asymptotic 2-tailed p-value is 0.0001.</p

Feature points with corresponding standard deviation (SD) error bars and piecewise cubic Hermite interpolated polynomial fits [<b>22</b>] of arterial and cerebrospinal fluid (CSF) flow in the elderly (gray line) and young groups (dashed black line) as a function of time.

<p>The left column <b>A</b>–<b>C</b> shows results for females, right for males <b>D</b>–<b>F</b>. Top row: Sum of mean (over subjects) normalized flow velocity curves in the left and right common carotid arteries and the left and right vertebral arteries. Middle row: Mean CSF flow in the cervical spinal canal at the level of C3–C4 (between the third and fourth vertebrae). Positive values correspond to flow in cranial direction. Bottom row: Mean CSF flow in the aqueduct (positive values: cranial flow). In panels <b>A</b> and <b>D</b>, the feature points are labeled ar1–ar6, in <b>B</b> and <b>E</b> sp1–sp6 and in <b>C</b> and <b>F</b> aq1–aq5 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037502#pone-0037502-t002" target="_blank">Table 2</a>).</p

Mean and standard deviation (SD) of subjects' age, body mass index (BMI) and height, as well as aqueductal stroke volume [101] and average flow rate [11], (1).

<p>The average (avg) spinal CSF and systolic (syst) arterial flows used to normalize the data are listed. Significant differences and correlations are summarized below.</p><p>Difference between female and male volunteers:</p>*<p>P = 0.033;</p>**<p>P = 0.028.</p><p>Correlation in entire population of height with age  = 0.44, P = 0.04; and sex  = 0.75, P0.0001.</p><p>Correlation of height with sex in young group  = 0.87, P = 0.0006; and in elderly group  = 0.70, P = 0.017.</p

Cross-correlation of arterial input to cervical spinal A (at the level of C3–C4) and to aqueductal B cerebrospinal fluid flow, mean (bold line) and standard deviation (gray shading) of elderly (gray line) and young (black line) groups' results.

<p>The vertical lines depict the mean delays from the maximum systolic peak flows to the maximum caudal flows in either CSF compartment.</p

Stent malapposition and its effect on local hemodynamics.

<p>(A) Imprint of malapposed stent end section (arrow) in artery lumen negative (top) and corresponding wall shear stress (WSS) distribution (bottom). Higher WSS can be observed in the vicinity of the malapposed strut due to flow tunneling compared to (B), where a similar fully apposed stent end section is shown. (C) Velocity contour in axial cross-section of the stented artery near a malapposed strut. Changes in velocity and division of blood flow can be seen. (D) Velocity vector plot in the vicinity of the malapposed strut demonstrates the presence of vortices. These influence WSS distribution and may lead to thrombosis.</p

Axial arterial deformation due to stenting.

<p>(A) Visualization of arterial centerline change in a stented section. The solid line shows the axis of the stent, while the dashed line approximates the centerline of the stent-free artery. (B) Wall shear stress (WSS) distribution in the same stented artery. An extended area of low WSS is seen immediately downstream of the stent at the outer artery wall due to the change in curvature.</p

Velocity profiles in a porcine left coronary artery with two stents.

<p>Results are shown for cross-sections upstream of the distal stent (A and B), within (C, D E and F) and downstream of the stent (G and H). <i>Top:</i> Velocity contour plots. <i>Bottom:</i> Velocity projections onto axial planes. The vertical axes are normalized to a common diameter.</p

Oscillatory shear index (OSI) distribution in a porcine left coronary artery with two stents.

<p>The inset shows a magnified view of part of the second stented segment. Elevated values of OSI have been reported to correlate with atheroprone vessel regions <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058147#pone.0058147-Rikhtegar1" target="_blank">[17]</a>. Areas of increased OSI are visible near strut junctions. They contain small focal spots that reach values close close to the maximum of 0.5.</p