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In "antegrade" flow, the blood flows according to the normal flow within the circulatory system (e.g. veins flow towards the heart while arteries flows away from the heart). In "retrograde" flow, the flow would reverse (e.g. veins flow away from heart or arteries flow towards the heart). However, "retrograde" flow can be both abnormal or normal.
Doppler measurements using Doppler effect can show the direction of the blood flow and its relative velocity, and color Doppler is the provision of color to help interpret the image, showing, for example, the blood flow toward the probe in one color and that flowing away in another. While the equipment itself is costly, the procedure is not.
Duplex ultrasound (duplex) combines standard B-mode ultrasound and Doppler ultrasonography to evaluate both structural details of the carotid arteries and blood flow through the arteries. [2] During carotid duplex evaluation, the 2D B-mode structural image is superimposed with the doppler flow data, which provides a more realistic anatomical ...
Some authors indicate the presence of venous type Doppler flow which reflects the portal venous nutrition of the nodule as a characteristic feature of dysplastic nodules and early HCC (Minami & Kudo, 2010). Other authors noticed the presence of an arterial flow with small frequency variations and a normal resistivity index.
In biomedical engineering, seeding is used to study blood flow in arteries and airflow in the respiratory system. For example, in cardiovascular research, small particles are added to fluids that mimic blood to visualize and measure flow patterns within arteries, especially at locations where blockages or aneurysms may occur. This helps ...
The pumping action of the heart generates pulsatile blood flow, which is conducted into the arteries, across the micro-circulation and eventually, back via the venous system to the heart. During each heartbeat, systemic arterial blood pressure varies between a maximum ( systolic ) and a minimum ( diastolic ) pressure. [ 33 ]
A smaller positive peak at the end of systole indicating that the deceleration of blood at the end of systole is predominantly due to a forward deceleration wave instead of backward reflected waves. The very low level of net wave intensity during diastole; Departures from this pattern of wave intensity is usually indicative of pathology. Figure 3.
The photoacoustic Doppler effect is a type of Doppler effect that occurs when an intensity modulated light wave induces a photoacoustic wave on moving particles with a specific frequency. The observed frequency shift is a good indicator of the velocity of the illuminated moving particles. A potential biomedical application is measuring blood flow.