Doppler Instrumentation and Hemodynamics Flashcards
a misrepresnetation of the doppler shift in a negative direction occuring when the pulse repetition frequency is set to low
aliasing
smallest arteries in the circulatory system controlling the needs of organs and tissues
arterioles
pressure reduction in a region of high flow speed
bernoulli effect
auscultatory sound within an artery produced by turbulent blood flow
bruit
the smallest of the body’s blood vessels connecting the arteriolies and venules and allowing the interchange of oxygen or carbon dioxide and nutrients to the tissue cells
capillaries
noise in the doppler signal caused by high amplitude doppler shifts
clutter
observed frequency change of the reflected sound resulting from movement relative to the sound source or observer
doppler effect
frequency shift created between the transmitted frequency and received frequency by an interface moving with velocity at an angle to the sound
doppler shift
energy difference between two points
energy gradient
to move in a stream, continually changing position and direction
flow
electronic device controlling the transmission or reception of a doppler signal; size of the gate is determined by the beam diameter, reciever gate length, and length of ultasound pulse
gate
twisting type of blood flow
helical flow
science or physical principles concerned with the study of blood circulation
hemodynamics
the perceived color; any one or a combination of primary colors
hue color map
the pressure created in a fluid system, such as circulatory system; when supine, the hydrostatic pressure is 0 mmHg. when upright the pressure is negative above the heart and positive below the heart
hydrostatic pressure
the resistance to acceleration
inertia
consists of the arterioles, capillaries and venules
microcirculation
the highest frequency in a samples signal represented unambiguously; equal to one half the pulse rep frequency
nyquist limit
positioning of multiple pulsed doppler gates over the area of interest
packet
maximum velocity at any given time
peak velocity
speed is constant across the vessel
plug flow
predits volume flow in a cyndrical vessel
poiseuille’s equation
difference in pressure required for flow to occur
pressure gradiant
a parameter used to convey the pulsatility of a time-varying waveform
pulsatility index
predicts the onset of turbulent flow
reynolds number
difference between the max and min doppler frequency shifts divided by the max doppler frequency shift; also known as pourcelot index
resistant index
electronic device that controls the region of the doppler flow detection
sample volume
degree to ehich the original color is diluted with white; the paler the color (or the less saturated it is), the faster the flow velocity; the purer the color, the slower the flow velocity
saturation color map
increase in the range of doppler shift frequencies displayed resulting in a loss of spectral window; ususally seen with stenosis
spectral broadening
amount of blood moving in a forward direction; blood being ejected
stroke volume
the average velocity id calculated, with the colors placed side to side
variance mode
rate of motion with respect to time
velocity
all measured velocitied for each gate are averaged, then colors are arranged up and down
velocity mode
the smallest veins that receive blood from capillaries and drain into larger caliber veins
venules
the quantity of blood moving trough the vesssel per unit of time
volume flow rate
types of arterial blood flow
laminar parabolic flow plug pulsatile disturbed turbulant
types of venous flow
augmentation phasic proximal pressure spontaneous unidirectional
