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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.
For this reason, the blood flow velocity is the fastest in the middle of the vessel and slowest at the vessel wall. In most cases, the mean velocity is used. [18] There are many ways to measure blood flow velocity, like videocapillary microscoping with frame-to-frame analysis, or laser Doppler anemometry. [19]
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 ...
Medical ultrasound includes diagnostic techniques (mainly imaging techniques) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics (e.g., distances and velocities) or to generate an informative audible sound.
Venous blood with an oxygen concentration of 15 mL/100 mL would therefore lead to typical values of the a-vO 2 diff at rest of around 5 mL/100 mL. During intense exercise, however, the a-vO 2 diff can increase to as much as 16 mL/100 mL due to the working muscles extracting far more oxygen from the blood than they do at rest. [citation needed]
Unlike arterial ultrasonography, venous ultrasonography is carried out with the probe in a transversal position, (perpendicular to the vein axis), displaying cross-sections of the veins. [4] All collateral veins are better detected this way, including perforator veins, but of most importance is the detection of venous thrombosis.
In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. [1] [2] It includes the cardiovascular system, or vascular system, that consists of the heart and blood vessels (from Greek kardia meaning heart, and Latin vascula meaning vessels).