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The condition and health of the common carotid arteries is usually evaluated using Doppler ultrasound, CT angiography or phase contrast magnetic resonance imaging (PC-MRI). Typically, blood flow velocities in the common carotid artery are measured as peak systolic velocity (PSV) and end diastolic velocity (EDV).
The theory of the velocity of the transmission of the pulse through the circulation dates back to 1808 with the work of Thomas Young. [9] The relationship between pulse wave velocity (PWV) and arterial wall stiffness can be derived from Newton's second law of motion (=) applied to a small fluid element, where the force on the element equals the product of density (the mass per unit volume ...
The condition and health of the external carotid arteries is usually evaluated using Doppler ultrasound, CT angiogram or phase contrast magnetic resonance imaging (PC-MRI). Typically, blood flow velocities in the external carotid artery are measured as peak systolic velocity (PSV) and end diastolic velocity (EDV). [4]
Blood flow velocity is increased in areas of stenosis compared to normal. Therefore, doppler imaging substantially aids in the diagnosis of carotid artery stenosis by ultrasound. [ 2 ] Internal carotid artery (ICA) is located posterolateral, and larger when compared to the external carotid artery (ECA).
Typically internal carotid artery blood flow velocities are measured in peak systolic velocity (PSV) and end diastolic velocity (EDV) and according to Society of Radiologists in Ultrasound in healthy subjects without stenosis must be below 125 cm/sec at PSV and below 40 cm/sec at EDV. [10]
Velocity Time Integral is a clinical Doppler ultrasound measurement of blood flow, equivalent to the area under the velocity time curve. The product of VTI (cm/stroke) and the cross sectional area of a valve (cm2) yields a stroke volume (cm3/stroke), which can be used to calculate cardiac output.
A Reynolds number of less than 2300 is laminar fluid flow, which is characterized by constant flow motion, whereas a value of over 4000, is represented as turbulent flow. [16] Due to its smaller radius and lowest velocity compared to other vessels, the Reynolds number at the capillaries is very low, resulting in laminar instead of turbulent flow.
The relationship between arterial stiffness and pulse wave velocity was first predicted by Thomas Young in his Croonian Lecture of 1808 [11] but is generally described by the Moens–Korteweg equation [12] or the Bramwell–Hill equation. [13] Typical values of PWV in the aorta range from approximately 5 m/s to >15 m/s. [14]