Doppler Flow Meter
Doppler Flow Meter - Related Videos
09:28
Using a pH Meter
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2023
Source: Laboratory of Dr. Zhongqi He - United States Department of Agriculture Acids and bases are substances capable of donating protons (H+) and hydroxide ions (OH-), respectively. They are two extremes that describe chemicals. Mixing acids and bases can cancel out or neutralize their extreme effects. A substance that is neither acidic nor basic is neutral. The values of proton concentration ([H+]) for most solutions are inconveniently small and difficult to compare so that a more practical...
03:47
Functional Imaging of Cerebral Blood Flow Using Transcranial Doppler Ultrasound
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2025
Source: Hage, B. D. et. al., Functional Transcranial Doppler Ultrasound for Monitoring Cerebral Blood Flow. J. Vis. Exp. (2021) This video demonstrates the use of Doppler ultrasound as a functional imaging tool to measure cerebral blood flow velocity, or CBFV in real time. It highlights how frequency shifts in the middle cerebral artery during tasks like breath-holding reveal changes in CBFV, offering insights into brain activity and vascular dynamics.
09:12
Sound Waves and Doppler Shift
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2023
Source: Arianna Brown, Asantha Cooray, PhD, Department of Physics & Astronomy, School of Physical Sciences, University of California, Irvine, CA Waves are disturbances that propagate through a material medium or empty space. Light waves can travel through a vacuum and some forms of matter, and are transverse in nature, which means that the oscillations are perpendicular to the direction of propagation. However, sound waves are pressure waves that travel through an elastic medium like air,...
05:57
Blood Flow Imaging with Ultrafast Doppler
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Cited by 10 •
2020
This protocol shows how to apply ultrafast ultrasound Doppler imaging to quantify blood flows. After a 1 s long acquisition, the experimenter has access to a movie of the full field of view with axial velocity values for each pixel every ≈0.3 ms (depending on the ultrasound time of flight).
02:22
Positioning Laser Doppler Probe: A Technique to Implant Probe Over Middle Cerebral Artery for Blood Flow Measurement in Murine Model
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2025
This video describes the surgical procedure to immobilize the laser Doppler probe over the murine brain's middle cerebral artery, or MCA. The probe helps to measure the blood flow in the brain's microvasculature by measuring the Doppler shift caused due to the motion of red blood cells within the artery.
FAQs
The transducer sends high-frequency ultrasound into a vessel, where moving red blood cells reflect the signal. Their motion changes the frequency of the returning waves. The measured size of that Doppler shift provides an indication of blood-flow velocity, allowing the instrument to turn reflected sound information into a hemodynamic measurement.
They act as moving reflectors within the vessel. Because the cells move with blood, the reflected signal carries information about movement within the vessel. Analyzing this change enables assessment of not only how quickly blood is moving but also the direction of flow. Thus, cellular reflection links ultrasound observations with circulation.
A narrowing or obstruction alters the movement of blood through the affected vessel. Because the instrument detects changes in blood-flow velocity and direction, its readings can reveal altered circulation rather than merely confirming that fluid is present. Clinicians can therefore use the resulting flow information to identify hemodynamic changes associated with vascular narrowing or obstruction.
An ultrasound transducer is directed into the region of interest and emits high-frequency signals. Moving blood cells reflect those signals back, producing a frequency shift. The instrument analyzes the returned waves and reports flow-related information, including velocity and direction. This sequence supports a noninvasive assessment of circulation without requiring direct access to the vessel.
It is useful when clinicians need to evaluate circulation, investigate flow changes that may accompany vascular narrowing or obstruction, or monitor blood movement over time. The method provides information without direct access to the vessel, making it suitable for diagnostic assessment and for observing hemodynamic changes in medical settings.
In research settings, measurements can characterize blood movement by documenting velocity and direction, then support evaluation of hemodynamic changes. These data help investigators examine vascular function and compare circulation-related findings across diagnostic or experimental observations. The value lies in translating reflected-sound changes into interpretable information about movement within vessels.