Matches in SemOpenAlex for { <https://semopenalex.org/work/W1553659639> ?p ?o ?g. }
Showing items 1 to 59 of
59
with 100 items per page.
- W1553659639 endingPage "150" @default.
- W1553659639 startingPage "149" @default.
- W1553659639 abstract "Wall shear stress is hypothesized to be an important factor in the localization and the development of arterial disease. Wall shear stress is calculated by multiplying wall shear rate by the viscosity. Wall shear rate can be estimated by velocity gradient from the velocity profile. Velocity can be measured in vivo by Phase Contrast Magnetic Resonance Imaging. We focused on evaluating wall shear rate using pixel-by-pixel based velocity data from MR imaging. We used interpolation method to find polynomials of velocity. In this study, Lagrange's polynomial interpolation is used. The measurement equation for wall shear rate is induced from derivative of the interpolated polynomial of velocity. Since wall shear stress is determined by multiplication of the viscosity of blood and wall shear rate, it can be calculated using estimated wall shear rate value. Our method was verified using data from a flow model system of aorta. Wall shear rate and wall shear stress are reliably measured by derived equation. BACKGROUND Hemodynamic factors give information about causes of dysfunction and disease of blood vessels. In particular, wall shear stress has the strong correlation with the localization of atherosclerosis and aneurysms and is important in understanding the development of arterial disease [1]. However, in vivo wall shear stress measurement has many limitations and difficulties. Thus, noninvasive measurement methods have been studied in many ways. We suggest that a mathematical measurement method using pixel-by-pixel based velocity data and Lagrange's interpolation. METHODS First, velocity profile was needed to calculate wall shear stress. MR imaging is performed with velocity encoded phase contrast sequence. Using the in house-developed velocimetry program, velocity value can be calculated by pixel-by-pixel based. We assume that blood vessels are of the cross sectional shape of circle. The center of vessel is chosen and pixels of wall position are set in each image. Next, we estimate polynomials that satisfied given velocity value using Lagrange’s polynomial interpolation. For an arbitrary calculation point on the wall location, three reference points are selected from a targeting point to the center. Points located at the wall is set by (x0, y0) and all points can be represented by (xi, yi)=(distance from x0, velocity), i=1, 2, 3 (1) Using pixel information of four points, a third ordered polynomial P(x) is calculated. The derivative of polynomial at the wall position is wall shear rate. Finally, wall shear stress (τω) is calculated by multiplying wall shear rate (P'(0)) and the viscosity of blood (μ)." @default.
- W1553659639 created "2016-06-24" @default.
- W1553659639 creator A5010572665 @default.
- W1553659639 creator A5017745289 @default.
- W1553659639 creator A5040409719 @default.
- W1553659639 creator A5046688257 @default.
- W1553659639 creator A5049512739 @default.
- W1553659639 creator A5058563246 @default.
- W1553659639 creator A5078305561 @default.
- W1553659639 date "2011-11-01" @default.
- W1553659639 modified "2023-09-23" @default.
- W1553659639 title "Mathematical Measurement of Aortic Wall Shear Stress" @default.
- W1553659639 hasPublicationYear "2011" @default.
- W1553659639 type Work @default.
- W1553659639 sameAs 1553659639 @default.
- W1553659639 citedByCount "0" @default.
- W1553659639 crossrefType "journal-article" @default.
- W1553659639 hasAuthorship W1553659639A5010572665 @default.
- W1553659639 hasAuthorship W1553659639A5017745289 @default.
- W1553659639 hasAuthorship W1553659639A5040409719 @default.
- W1553659639 hasAuthorship W1553659639A5046688257 @default.
- W1553659639 hasAuthorship W1553659639A5049512739 @default.
- W1553659639 hasAuthorship W1553659639A5058563246 @default.
- W1553659639 hasAuthorship W1553659639A5078305561 @default.
- W1553659639 hasConcept C121332964 @default.
- W1553659639 hasConcept C127172972 @default.
- W1553659639 hasConcept C159985019 @default.
- W1553659639 hasConcept C165682214 @default.
- W1553659639 hasConcept C192562407 @default.
- W1553659639 hasConcept C196558001 @default.
- W1553659639 hasConcept C21141959 @default.
- W1553659639 hasConcept C2524010 @default.
- W1553659639 hasConcept C33923547 @default.
- W1553659639 hasConcept C57879066 @default.
- W1553659639 hasConcept C94656876 @default.
- W1553659639 hasConcept C96035792 @default.
- W1553659639 hasConceptScore W1553659639C121332964 @default.
- W1553659639 hasConceptScore W1553659639C127172972 @default.
- W1553659639 hasConceptScore W1553659639C159985019 @default.
- W1553659639 hasConceptScore W1553659639C165682214 @default.
- W1553659639 hasConceptScore W1553659639C192562407 @default.
- W1553659639 hasConceptScore W1553659639C196558001 @default.
- W1553659639 hasConceptScore W1553659639C21141959 @default.
- W1553659639 hasConceptScore W1553659639C2524010 @default.
- W1553659639 hasConceptScore W1553659639C33923547 @default.
- W1553659639 hasConceptScore W1553659639C57879066 @default.
- W1553659639 hasConceptScore W1553659639C94656876 @default.
- W1553659639 hasConceptScore W1553659639C96035792 @default.
- W1553659639 hasIssue "2" @default.
- W1553659639 hasLocation W15536596391 @default.
- W1553659639 hasOpenAccess W1553659639 @default.
- W1553659639 hasPrimaryLocation W15536596391 @default.
- W1553659639 hasVolume "6" @default.
- W1553659639 isParatext "false" @default.
- W1553659639 isRetracted "false" @default.
- W1553659639 magId "1553659639" @default.
- W1553659639 workType "article" @default.