Ultrasound Review - Ch 5 - Physics/doppler Instrumentation & Hemodynamics

Front 1

A major cellular component of blood is the:

a) plasma

b) platelet

c) leukocyte

d) erythrocyte

Back 1

d) erythrocte

Front 2

Which of the following is an auscultatory consequence of turbulent flow?

a) bruit

b) disturbed flow

c) high resistance

d) velocity increase

Back 2

a) bruit

Front 3

Which of the following is the most accurate definition of hemodynamics?

a) the pressure created in a fluid system

b) a fluid's ability to resist change in shape or flow

c) the pressure difference required for blood to flow

d) the physical principles concerned with the study of blood circulation

Back 3

d) the physical principles concerned with the study of blood circulation

Front 4

What type of arterial blood flow exhibits a constant velocity across the vessel?

a) plug

b) laminar

c) pulsatile

d) parabolic

Back 4

a) plug

Front 5

The microcirculation consists of the:

a) arteries and veins

b) arterioles and venules

c) arterioles, capillaries, and venules

d) arteries, veins, venules, and capillaries

Back 5

c) arterioles, capillaries, & venules

Front 6

Which portion of the circulatory system exchanges vital nutrients with tissue cells?

a) aorta

b) venules

c) arterioles

d) capillaries

Back 6

d) capillaries

Front 7

Which of the following will most likely resolve aliasing?

a) decreasing the Doppler angle

b) increasing the operating frequency

c) increasing the PRP

d) decreasing the depth of the sample volume

Back 7

d) decreasing the depth of the sample volume

Front 8

A positive Doppler shift occurs when the:

a) spectral information is displayed below the baseline

b) received frequency is less than the transmitted frequency

c) received frequency is greater than the transmitted frequency

d) transmitted frequency is greater than the received frequency

Back 8

c) received frequency is greater than the transmitted frequency

Front 9

Which of the following will most likely increase the system's sensitivity of the Doppler shifts?

a) increasing the Doppler angle

b) repositioning the sample volume

c) increasing the operating frequency

d) decreasing the size of the sample gate

Back 9

c) increasing the operating frequency

Front 10

If the received and transmitted frequencies are identical, which of the following will occur?

a) no Doppler shift

b) positive Doppler shift

c) negative Doppler shift

d) proportional Doppler shift

Back 10

a) no Doppler shift

Front 11

A major advantage of continuous wave Doppler is the:

a) ease of use

b) small probe size

c) ability to measure high velocities

d) interrogation of multiple vessels simultaneously

Back 11

c) ability to measure high velocities

Front 12

The Doppler equation determines the:

a) volume flow rate

b) Reynolds Number

c) cosine of the Doppler angle

d) change in the transmitted & received frequencies

Back 12

d) changes in the transmitted & received frequencies

Front 13

Which of the following is the most consistent predictor of turbulent flow?

a) Doppler shift

b) resistive index

c) pressure gradient

d) Reynolds number

Back 13

d) Reynolds number

Front 14

Which of the following is required for blood flow to occur?

a) Doppler shift

b) kinetic energy

c) pressure gradient

d) high cardiac output

Back 14

c) pressure gradient

Front 15

The speed at which blood travels through a vessel is more likely dependent on which of the following?

a) volume flow rate

b) size of the capillaries

c) left ventricular output

d) resistance of the venules

Back 15

c) left ventricular output

Front 16

In which of the following positions is venous pressure the lowest?

a) erect

b) supine

c) decubitus

d) semierect

Back 16

b) supine

Front 17

The greatest portion of circulating blood is located in the:

a) brain

b) heart

c) venous system

d) arterial system

Back 17

c) venous system

Front 18

What type of blood flow occurs if the average flow velocity is equal to 1/2 the maximum flow speed in the center?

a) plug flow

b) laminar flow

c) pulsatile flow

d) parabolic flow

Back 18

d) parabolic flow

Front 19

Normal respiratory variations in venous blood flow are termed:
a) phasic

b) pulsatile

c) spontaneous

d) bidirectional

Back 19

a) phasic

Front 20

Which of the following is a disadvantage of duplex imaging?

a) decrease in imaging frame rate

b) combines imaging and Doppler information

c) allows measurement only of mean velocities

d) inability to use high operating frequencies

Back 20

a) decrease in frame rate

Front 21

Noise within the Doppler signal is known as:

a) flash

b) clutter

c) aliasing

d) acoustic speckle

Back 21

b) clutter

Front 22

Which of the following is the driving force of blood flow?

a) velocity

b) pressure

c) resistance

d) volume flow rate

Back 22

b) pressure

Front 23

Observed frequency changes in moving structures most accurately define:

a) Doppler shift

b) nyquist limit

c) doppler effect

d) pressure gradient

Back 23

c) Doppler effect

Front 24

The Nyquist limit is equal to:

a) the operating frequency

b) the peak systolic velocity

c) the pulse repetition frequency

d) one half of the PRF

Back 24

d) 1/2 the PRF

Front 25

What type of color Doppler mapping displays a combination of primary colors?

a) hue

b) mosaic

c) variance

d) saturation

Back 25

a) hue

Front 26

Thickening of the spectral trace is most likely a result of:

a) the reverberation artifact

b) low amplitude Doppler shifts

c) an increase in the range of Doppler shift frequencies

d) the quantity of blood moving through the sample gate

Back 26

c) an increase in the range of Doppler shift frequencies

Front 27

The size of the sample volume is determined by the beams diameter, length of the ultrasound pulse and:

a) Doppler shift

b) Doppler angle

c) operating frequency

d) receiver gate length

Back 27

d) receiver gate length

Front 28

Which of the following converts Doppler shift information into a visual spectral display?

a) scan converter

b) autocorrelation

c) fast Fourier transform

d) digital analog converter

Back 28

c) FFT

Front 29

In color flow Doppler, multiple sample gates positioned in the area of interest are termed:

a) pixels

b) voxels

c) packets

d) color volumes

Back 29

c) packets

Front 30

Which of the following correctly describes the hemodynamics of blood flow?

a) blood only flows when pressures are equal

b) blood flows from low pressure to high pressure

c) blood flows from higher pressure to lower pressure

d) blood flows from higher velocity to lower velocity

Back 30

c) blood flows from higher pressure to lower pressure

Front 31

Increasing the operating frequency will:

a) overcome aliasing

b) increase the packet size

c) increase the Nyquist limit

d) increase the sensitivity to low Doppler shifts

Back 31

d) increase the sensitivity to low Doppler shifts

Front 32

The greater the pressure gradient, the greater the:

a) flow velocity

b) flow resistance

c) Reynolds number

d) blood flow volume

Back 32

d) blood flow volume

Front 33

Resistance to blood flow is proportional to the:

a) flow velocity

b) Reynolds number

c) blood flow volume

d) length of the vessel

Back 33

d) length of the vessel

Front 34

Which of the following occurs during inspiration?

a) abdominal and thoracic pressure increase

b) abdominal pressure decreases & thoracic pressure increases

c) abdominal pressure increases & thoracic pressure decreases

d) abdominal pressure decreases & thoracic pressure remains unchanged

Back 34

c) abdominal pressure increases & thoracic pressure decreases

Front 35

Which of the following is the simplest form of Doppler?

a) color

b) amplitude

c) pulse wave

d) continuous wave

Back 35

d) continuous wave

Front 36

The vertical axis of a spectral analysis represents:

a) time

b) motion

c) intensity

d) frequency

Back 36

d) frequency

Front 37

Rate of motion with respect to time defines:

a) energy

b) inertia

c) velocity

d) acceleration

Back 37

c) velocity

Front 38

Poiseuille's equation predicts:

a) the onset of aliasing

b) the onset of turbulence

c) resistance to acceleration

d) flow volume in a cylindrical vessel

Back 38

d) flow volume in a cylindrical vessel

Front 39

Pulse wave Doppler uses a maximum of:

a) 5 cycles per pulse

b) 15 cycles per pulse

c) 20 cycles per pulse

d) 30 cycles per pulse

Back 39

d) 30 cycles per pulse

Front 40

Color Doppler frequency shifts are obtained using:

a) beam profiler

b) scan converter

c) autocorrelation

d) fast Fourier transfer

Back 40

c) autocorrelation

Front 41

Demonstrating nonvascular motion is generally accomplished using:

a) color Doppler

b) spectral analysis

c) pulse wave Doppler

d) continuous wave Doppler

Back 41

a) color Doppler

Front 42

Power Doppler imaging displays the signal's:

a) energy

b) velocity

c) amplitude

d) frequency shift

Back 42

c) amplitude

Front 43

Increasing the Doppler angle is a method of overcoming:

a) flash

b) aliasing

c) mirror imaging

d) range ambiguity

Back 43

b) aliasing

Front 44

Smaller arteries commonly demonstrate:

a) plug flow

b) laminar flow

c) parabolic flow

d) turbulent flow

Back 44

b) laminar flow

Front 45

Increasing the packet size of color Doppler will decrease the:

a) accuracy

b) frame rate

c) sensitivity

d) Doppler shift

Back 45

b) frame rate