Investigation of the Boundary Layer Blood Flow and the Initial Factors of Atherosclerosis by the Magnetic Resonance Imaging | Chapter 03 | Emerging Research in Medical Sciences Vol. 2
Aim:
study the blood flow and vessel wall viscoelastic alterations at the boundary
layer and initial factors of atherosclerosis.
Study
Design: Magnetic resonance angiography with
the follow up flow quantification was carried out voluntary on the healthy
persons.
Place and Duration of Study: MRI department of the Institute of Clinical Medicine in Tbilisi Rep. Georgia, between September 2012 and July 2017.
Methodology:
In 12 healthy men (18-52 years of age) at the different sites of the aorta peak
velocity, net flow, flow acceleration has been investigated by Magnetic
Resonance Angiography. Blood radiodensity (HU) were studied (CT) in different
sites of the aorta and vena cava.
Results:
In the aortic arch in the end systole blood flow separates into the opposite
directed streams resulting in the wave superposition. At the outer curvature of
the isthmus, flow acceleration in the initial diastole is 6.26 times higher
than that in systole. Net flow from systole to diastole increases 2.5±0.5
folds. From the end systole to the initial diastole there is a plateau on the
net flow graph. At the outer curvature of isthmus, group wave at the boundary
reflection, changes in phase at 180°. At the same time flow wave oscillation
frequency at the outer curvature is two times higher (1.6Hz.) than that at the
inner (0.8Hz).
Conclusion:
During the heart cycle, blood motion at the boundary layer, forms the surface
wave and facilitates the blood structural rearrangement and flow. At the end
systole, at the outer curvature of the isthmus, pulse pressure at the
reflection is in the resonance with the end systolic pressure drop. Amplitude
of the wall stress increases. Forming standing wave leads to the dissipation of
the wall’s mechanical energy. Here, at the initial diastole, group wave, due to
the wave reflection, and frequency dispersion, facilitates to the structural
rearrangement/denudation of the vessel wall.
Author(s) Details
M. Beraia
MRI Department, Institute of
Clinical Medicine. 13 Tevdore Mgvdeli
str. 0112. Tbilisi, Georgia.
G. Beraia
Medical student (B.S.)
Tbilisi State Medical University. 33 Vazha-Phshavela ave. 0177. Tbilisi.
Georgia.
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