5. Imaging Motion & Flow Flashcards by Jenessa Beatty

The _____ are the tiniest vessels in the circulatory system.

a. arteries
b. arterioles
c. capillaries
d. bile ducts
e. venules
f. veins

c. capillaries

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The characteristic of a fluid that offers resistance to flow is called ______.

a. resistance
b. viscosity
c. inertia
d. impedance
e. density

b. viscosity

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Poise is a unit of _____.

a. resistance
b. viscosity
c. inertia
d. impedance
e. density

b. viscosity

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Pressure is _____ per unit area.

a. resistance
b. viscosity
c. inertia
d. force

d. force

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Pressure is _____.

a. nondirectional
b. unidirectional
c. omnidirectional
d. all of the above
e. none of the above

c. omnidirectional

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Flow is a response to pressure ______ or _______.

a. difference, gradient
b. increase, decrease
c. fore, aft
d. presence, absence

a. difference, gradient

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The volumetric flow rate in a tube is determined by _____ difference and ______.

a. resistance, pressure
b. pressure, resistance
c. diameter, length
d. pressure, length

b. pressure, resistance

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Flow increases if _____ increase(s).

a. pressure difference
b. pressure gradient
c. resistance
d. a and b
e. all of the above

d. a and b

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While flow resistance increases, volumetric flow rate _____.

a. increases
b. decreases
c. is unchanged
d. depends on pressure

b. decreases

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If pressure difference is doubled, volumetric flow rate is ______.

a. unchanged
b. quartered
c. halved
d. doubled
e. quadrupled

d. doubled

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If flow resistance is doubled, volumetric flow rate is ______.

a. unchanged
b. quartered
c. halved
d. doubled
e. quadrupled

c. halved

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Flow resistance in a vessel depends on ______.

a. vessel length
b. vessel radius
c. blood viscosity
d. all of the above
e. none of the above

d. all of the above

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Flow resistance decreases with an increase in _______.

a. vessel length
b. vessel radius
c. blood viscosity
d. all of the above
e. none of the above

b. vessel radius

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Flow resistance depends most strongly on ______.

a. vessel length
b. vessel radius
c. blood viscosity
d. all of the above
e. none of the above

b. vessel radius

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Volumetric flow rate decreases with an increase in ________.

a. pressure difference
b. vessel radius
c. vessel length
d. blood viscosity
e. c and d

e. c and d

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When the speed of a fluid is constant across a vessel, the flow is called _____ flow.

a. volume
b. parabolic
c. laminar
d. viscous
e. plug

e. plug

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_______ flow occurs when straight parallel streamlines describing the flow are altered.

a. volume
b. turbulent
c. parabolic
d. disturbed

d. disturbed

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______ flow involves random and chaotic flow patterns, with particles flowing in all directions.

a. volume
b. turbulent
c. parabolic
d. disturbed

b. turbulent

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Turbulent flow is more likely _______ to a stenosis.

a. proximal
b. distal

b. distal

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A narrowing of the lumen of a tube is called a _______.

a. stenosis
b. gorge
c. titer
d. kink

a. stenosis

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Proximal to, at, and distal to a stenosis, ______ must be constant.

a. laminar flow
b. disturbed flow
c. turbulent flow
d. volumetric flow rate
e. none of the above

d. volumetric flow rate

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Poiseuille equation predicts a(n) _____ in flow speed with a decrease in vessel radius.

a. increase
b. decrease

b. decrease

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The continuity rule predicts a(n) _____ in flow speed with a localized decrease (stenosis) in vessel diameter.

a. increase
b. decrease

a. increase

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In a stenosis, the pressure is _____ the proximal and distal values.

a. less than
b. equal to
c. greater than
d. depends on the fluid
e. none of the above

a. less than

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Added forward flow and flow reversal in diastole can occur with _____ flow. a. volume b. turbulent c. laminar d. disturbed e. pulsatile

e. pulsatile

While stenosis diameter decreases, ______ pass(es) through a maximum. a. flow speed at the stenosis b. flow speed proximal to the stenosis c. volumetric flow rate d. the Doppler shift at the stenosis e. a and d

e. a and d

The _____ effect is used to detect and measure ____ in vessels. a. Bernoulli, blood b. Poiseuille, pressure c. Poiseuille, flow d. Doppler, flow

d. Doppler, flow

Motion of an echo-generating structure causes an echo to have a different ______ from that of the emitted pulse. a. form b. strength c. amplitude d. frequency

d. frequency

If the incident frequency is 1 MHz, the propagation speed is 1600 m/s, and the reflector speed is 16 m/s toward the source, the Doppler shift is ___ MHz, and the reflected frequency is ____ MHz. a. -.-02, 1.02 b. 0.02, 1.02 c. 0.026, 1.026 d. -0.026, 1.026

b. 0.02, 1.02

For an operating frequency of 6 MHz, a flow speed of 50 cm/s, and a Doppler angle of 60 degrees, calculate the Doppler shift (kHz). a. 1.95 b. 9.15 c. 5.91 d. 5.19

a. 1.95

For blood flowing in a vessel with a plug flow profile, the Doppler shift is ___ across the vessel. a. constant b. variable c. parabolic d. circular

a. constant

Which Doppler angle yields the greatest Doppler shift? a. -90 b. -45 c. 0 d. 45 e. 90

c. 0

To proceed from a measurement of Doppler-shift frequency to a calculation of flow speed, ____ _____ must be known or assumed. a. pressure amplitude b. peak frequency c. Doppler angle d. average intensity

c. Doppler angle

If operating frequency is doubled, the Doppler shift is _____. a. halved b. unchanged c. doubled d. quadrupled

c. doubled

If flow speed is doubled, the Doppler shift is _____. a. halved b. unchanged c. doubled d. quadrupled

c. doubled

If Doppler angle is doubled, the Doppler shift is _____. a. doubled b. halved c. increased d. decreased

d. decreased

Color-Doppler instruments present two-dimensional, color-coded images representing _____ that are superimposed on gray-scale images representing ______. a. flow, anatomy b. motion, flow c. anatomy, frequency d. amplitude, frequency

a. flow, anatomy

Which of the following on a color-Doppler display is (are) presented in real time? a. gray-scale anatomy b. flow direction c. doppler spectrum d. a and b e. all of the above

d. a and b

Color-Doppler instruments use an ____ technique to yield Doppler information in real time. a. automatic b. autocorrelation c. autonomic d. autocratic

b. autocorrelation

The angle dependencies of Doppler-shift displays and Doppler-power displays are different. T or F?

True (power displays have no angle dependence)

In color-Doppler instruments, color is used only to represent flow direction. T or F?

False

About __ frames per second are produced by a color-Doppler instrument. a. 10 b. 20 c. 40 d. 80 e. More than one of the above

e. More than one of the above (a, b, or c)

Doppler shift displays are not dependent on Doppler angle. T or F?

False

If a color-Doppler instrument shows two colors in the same vessel, it always means flow is occuring in opposite directions in the vessel. T or F?

False (it also can mean aliasing or changing Doppler angle)

A region of bright color on a Doppler-shift display always indicates the highest flow speeds. T or F

False (remember the Doppler angle)

Increasing ensemble length ____ the frame rate. a. increases b. decreases c. doubles d. triples

b. decreases

The ______ technique is commonly used to detect echo Doppler shifts in color-Doppler instruments. a. automatic b. autocorrelation c. autonomic d. autocratic

b. autocorrelation

Which of the following reduces frame rate of a color-Doppler image? (more than one correct answer) a. wider color window b. longer color window c. increased ensemble length d. higher transducer frequency e. higher priority setting

a. wider color window and c. increased ensemble length

Lack of color in a vessel containing blood flow may be attributable to ______. (more than one correct answer) a. low color gain b. a high wall filter setting c. a low-priority setting d. baseline shift e. aliasing

a. low color gain, b. a high wall filter setting, c. a low-priority setting

Increasing ensemble length _____ color sensitivity and accuracy and _____ frame rate. a. improves, increases b. degrades, increases c. degrades, decreases d. improves, decreases e. none of the above

d. improves, decreases

Which control can be used to help with clutter? a. wall filter b. gain c. baseline shift d. PRF e. smoothing

a. wall filter

Color map baselines are always represented by ______. a. white b. black c. red d. blue e. cyan

b. black

Doubling the width of a color window produces a(n) _____ frame rate. a. doubled b. quadrupled c. unchanged d. halved e. quartered

d. halved

Steering the color window to the right or left produces a(n) ______ frame rate. a. doubled b. quadrupled c. unchanged d. halved e. quartered

c. unchanged

Autocorrelation produces _______. (more than one correct answer) a. the color of the Doppler shift b. the mean value of the Doppler shift c. variance d. spectrum e. peak Doppler shift

b. the mean value of the Doppler shift. c. variance

Steering the color window to the right or left changes ______. a. frame rate b. PRF c. the Doppler angle d. the Doppler shift e. more than one of the above

e. more than one of the above (the Doppler angle and shift)

Color-Doppler frame rates are ______ gray-scale rates. a. equal to b. less than c. more than d. depends on color map e. depends on priority

b. less than

In a single frame, color can change in a vessel because of ______. a. vessel curvature b. sector format c. helical flow d. diastolic flow reversal e. all of the above

e. all of the above

Angle is not important in transverse color-Doppler views through vessels. T or F?

False

Compared with Doppler-shift imaging, Doppler-power imaging is _______. a. more sensitive b. angle independent c. aliasing independent d. speed independent e. all of the above

e. all of the above

The functions of a Doppler detector include _______. a. amplification b. phase quadrature detection c. Doppler-shift detection d. sign determination e. all of the above

e. all of the above

An earlier gate time means _____ sample volume depth. a. a later b. a shallower c. a deeper d. a stronger e. none of the above

b. a shallower

Doppler signal power is proportional to _______. a. volume flow rate b. flow speed c. the Doppler angle d. cell concentration e. more than one of the above

d. cell concentration

Doppler ultrasound provides information about flow conditions only at the site of measurement. T or F?

False

Stenosis affects _______. a. peak systolic flow speed b. end diastolic flow speed c. spectral broadening d. window e. all of the above

e. all of the above

Spectral broadening is a _______ of the spectral trace a. vertical thickening b. horizontal thickening c. brightening d. darkening e. horizontal shift

a. vertical thickening

If all the cells in a vessel were moving at the same constant speed, the spectral trace would be a _____ line. a. thin horizontal b. thin vertical c. thick horizontal d. thick vertical e. none of the above

a. thin horizontal

Disturbed flow produces a narrower spectrum. T or F?

False

Turbulent flow produces a narrow spectrum. T or F?

False

As stenosis progresses, which of the following increase(s)? a. lumen diameter b. systolic Doppler shift c. diastolic Doppler shift d. spectral broadening e. more than one of the above

e. more than one of the above (systolic Doppler shift, diastolic Doppler shift, spectral broadening)

High flow speed always produces a higher Doppler shift on a spectral display. T or F?

False (remember the Doppler angle)

Flow reversal in diastole indicates _________. a. a stenosis b. an aneurysm c. high distal resistance d. low distal resistance e. more than one of the above

c. high distal resistance

If angle correction is set at 60 degrees but should be zero degrees, the display indicates a flow speed of 100 cm/s. The correct flow speed is ____ cm/s. a. 25 b. 50 c. 100 d. 200

b. 50

If angle correction is set at zero degrees but should be 60 degrees, the display indicates a flow speed of 100 cm/s. The correct flow speed is ____ cm/s. a. 25 b. 50 c. 100 d. 200

d. 200

If a 5 kHz Doppler shift corresponds to 100 cm/s, then a 2.5 kHz shift corresponds to ____ cm/s. a. 100 b. 75 c. 50 d. 25

c. 50

Which of the following is increased if Doppler angle is increased? a. aliasing b. Doppler shift c. effect of angle error d. b and c e. none of the above

c. effect of angle error