Davies Test Questions

Question 1

What is the time it takes for one pulse to occur known as?

Answer 1

Pulse Duration

Question 2

When you change the transmit frequency, what is altered?

Answer 2

Number of cycles per second

Question 3

What is the speed of sound defined as?

Answer 3

Speed at which the sound waves propagate through the medium

Question 4

What does Snell’s Law describe?

Answer 4

The angle of sound transmission at an interface between media having different propagation speeds.

Question 5

What interaction of ultrasound and tissue is primarily responsible for imaging the internal structure of organs?

Answer 5

Scattering

Question 6

If the number of cycles in a pulse is increased but the wavelength remains the same, what happens to the PD?

Answer 6

Pulse duration is increased

Question 7

Refraction is a bending of the sound beam that results in which misregistration?

Answer 7

Lateral registration

Question 8

The rate of sound attenuation is lowest in what?

Answer 8

Water

Question 9

Which of the following increases as frequency increases?

A. Absorption
B. Scattering
C. Attenuation
D. A and C only
E. All of the Above

Answer 9

E. All of the Above

Question 10

What does ultrasound propagation velocity depend on?

Answer 10

Density and compressibility

Question 11

The length of space over which one cycle occurs is known as what?

Answer 11

wavelength

Question 12

Axial resolution is determined mostly by what?

Answer 12

Pulse Duration

The shorter the pulse, the better the axial resolution

Question 13

According o Snell’s law, the angle of transmission is related to the incident beam angle and what?

Answer 13

The relative speeds of sound in the two media

Question 14

A longitudinal wave is characterized by what?

Answer 14

Particle motion occurring in the same direction as propagation

Question 15

What is another term for nonspecular reflection?

Answer 15

Scattering

Question 16

Relative measurement of intensity based on a logarithmic scale is expressed in which unit?

Answer 16

Decibels

Question 17

When you adjust the pulse repetition frequency, what are you changing?

Answer 17

The number of pulses per second

Question 18

The maximum cyclical change in a quantity is known as?

Answer 18

Amplitude

Question 19

As a general observation about media in diagnostic sonography, sound propagates faster in materials with greater what?

Answer 19

Stiffness

Question 20

What array transducer fires all of the elements for each acoustic scan line, using small time delays to steer the beam?

Answer 20

Phased array

Question 21

What type of resolution is most affected by Pulse Duration?

Answer 21

Axial (Axial resolution is determined by SPL, SPL and PD are DIRECTLY related)

Question 22

The inability to clearly demonstrate small cystic structures comes with a transducer with poor resolution of what? (Lateral, axial, elevational?)

Answer 22

Elevational

Question 23

What is another name for axial resolution?

Answer 23

Range resolution

Question 24

What is associated with a low-Q transducer?

Answer 24

Wide bandwidth, multifrequency selection, diagnostic PW ultrasound, loss of most energy in a first few vibrations - good axial resolution, so a short pulse length

Question 25

Varying the excitation voltage to each element in the group used to form the US pulse is called what?

Answer 25

Apodization

Question 26

What is parallel processing?

Answer 26

A method used to improve frame rates with multizone electronic focusing

Question 27

Which transducer should be selected to produce the narrowest slice thickness throughout the imaging plane?

Answer 27

1.5D multirow array

Question 28

What can you do to improve contrast resolution in the ultrasound image?

Answer 28

Use a 2D or matrix array transducer

Question 29

What does dynamic receive focusing use and do?

Answer 29

It uses time delays before echo signals from array elements are combined; results in constructive interference of the waves and produces a higher amplitude and more focused signal

Question 30

Multiple matching layers on a transducer face result in an increased what?

Answer 30

Bandwidth

Question 31

You think you see a calc on B-mode, but posterior acoustic shadow is not present. What is the best optimization for your system to demonstrate the shadow going to be?

Answer 31

Increase transducer frequency

Question 32

What is the purpose of curving the transducer elements or applying a lens over the elements?

Answer 32

Provides focusing in the out-of-plane direction (elevational)

Question 33

You are imaging a 3D dataset that has anisotropic resolution. What does this mean?

Answer 33

Unequal resolution is present between imaging planes

Question 34

The term Signal to Noise Ratio denotes what?

Answer 34

The relative amplitude of the signal compared to the amplitude of the noise

Question 35

What does increasing the threshold do to weak signals?

Answer 35

Reduces the display of weak signals

Question 36

What is the typical value for the duty factor in diagnostic imaging?

Answer 36

0.1-1%

Question 37

What does the range equation describe?

Answer 37

The relationship between round-trip pulse time and distance to the reflector

Question 38

What is a disadvantage of a water-path scanner?

Answer 38

Bubbles in the fluid can inhibit sound transmission into the body

Question 39

The range equation is used to determine what?

Answer 39

Reflector depth

Question 40

What information is present in the M-mode display?

Answer 40

Time, motion pattern, and amplitude

Question 41

What is another name for image memory?

Answer 41

Digital scan converter

Question 42

Pulse repetition period is the inverse of what?

Answer 42

Pulse repetition frequency

Question 43

What is a typical frame rate for B-mode real-time imaging?

Answer 43

10-50 Hz

Question 44

When you increase the scanning depth, which of the following is automatically decreased by the system to avoid range ambiguity?

Answer 44

PRF

Question 45

What is the order in which the signal travels in the ultrasound system?

Answer 45

Transducer, receiver, scan converter, display

Question 46

What is echo ranging?

Answer 46

A physical concept that allows us to determine the location of an interface by measuring the elapsed time between the transmitted pulsed ultrasound wave and the detected echo from that interface.

Question 47

What provides a thinner beam and improved contrast resolution?

Answer 47

Tissue Harmonic Imaging

Question 48

What is the purpose of the preamplification of the incoming signal that occurs in the transducer assembly?

Answer 48

To INCREASE echo voltages before noise is induced through the cable

Question 49

When changing the transmit frequency, what is altered?

Answer 49

Number of cycles per second

Question 50

The algebraic summation of waves leading to patterns of minima and maxima is called?

Answer 50

Interference

Question 51

Another term for nonspecular reflection is?

Answer 51

Scattering

Question 52

What factor determines the frequency of the sound wave for PULSED wave ultrasound?

Answer 52

Transmitter Frequency

Question 53

The speed is sound is defined as the...?

Answer 53

Speed at which the sound wave propagates through the medium

Question 54

When you perform a Doppler exam, the frequency of the transmitted signal is determined by what?

Answer 54

The frequency of the electrical signal applied to the transducer

Question 55

Acoustic impedance increases with what 2 things?

Answer 55

Increased tissue density & increased propagation speed

Question 56

When you adjust PRF, you are changing what?

Answer 56

The number of pulses per second

Question 57

Which of the following would increase the spatial pulse length?

Answer 57

Increased numbers of cycles per pulse

Question 58

What is constructive interference?

Answer 58

Sound waves are in phase and resulting amplitude is increased

Question 59

Interference patterns of reflected waves causes what?

Answer 59

Acoustic Speckle

Question 60

Another name for axial resolution is?

Answer 60

Range resolution

Question 61

What aspect of the Doppler spectrum is colour-encoded with colour Doppler?

Answer 61

Frequency Shift

Question 62

What is the name of the control that sets the gray-scale brightness at which colour will be displayed instead of gray-scale at a pixel location?

Answer 62

Priority

Question 63

What two controls affect the spatial resolution of the colour image?

Answer 63

Frequency and line density

Question 64

The most numerous cells are in the blood are in the?

Answer 64

Erythrocytes

Question 65

The Reynolds number increases with increasing...?

Answer 65

Flow speed, vessel diameter, blood density, blood flow viscosity

Question 65

What is the continuity rule?

Answer 65

The fact that the volumetric flow rate must be the same proximal, at, and distal to a stenosis

Question 66

What is the Bernoulli effect?

Answer 66

Pressure reduction in a region of high-flow speed.

Question 66

What is Poisueille's law?

Answer 66

The dependence of volume flow rate on pressure, vessel length and radius, and viscosity.

Question 67

When you encounter high velocities within a vessel, what best describes the Doppler frequency shift?

Answer 67

Frequency shift is increased

Question 68

Volume flow = cross section area x (what?)

Answer 68

Mean velocity

Question 69

Transducers should NOT be cleaned with:

Answer 69

Ultraviolet, autoclave, gas

Question 70

What is strain relief of a transducer?

Answer 70

The portion of the transducer that protects the insertion of the cable into the transducer housing. Prone to wear and tear.