SPI Practice Test

Which of the following do the source and the medium determine?

a. duty factor

b. frequency

c. propagation speed

d. axial resolution

d.

Axial resolution is affected by all of the following EXCEPT

a. frequency

b. damping

c. spatial pulse length

d. focusing

d.

Damping in a transducer

a. reduces the number of cycles in a pulse and increases the quality factor

b. increases the number of cycles in a pulse and increases penetration

c. causes poor axial and lateral resolution

d. reduces the duty factor and increases the range of transmitted frequencies

d.

Far zone beam divergence can be reduced on a single-element transducer by using

a. a transducer with a smaller element diameter

b. a higher frequency transducer

c. a lower frequency transducer or a smaller element diameter

d. adjustable focusing

b.

The area between the face of an unfocused single-element transducer and the point where the beam starts to diverge is the

a. Fraunhofer zone

b. refraction zone

c. focal zone

d. near zone

d.

Assuming a fixed frequency, what happens if the diameter of an unfocused transducer is increased?

a. the far zone divergence increases

b. the penetration decreases

c. the length of the near zone increases

d. the length of the near zone decreases

c.

Which of the following does NOT affect lateral resolution?

a. focusing

b. element diameter

c. frequency

d. bandwidth

d.

Higher frequency transducers provide

a. improved lateral resolution

b. smaller Doppler shifts

c. improved axial resolution and reduced attenuation

d. increased penetration

a.

Ultrasound waves that are traveling through a medium consist of

a. electromagnetic and radio frequencies

b. compressions and refractions

c. electromagnetic and ionizing frequencies

d. compressions and rarefactions

d.

What is the difference between audible sound and ultrasound?

a. audible sound waves can travel through a vacuum

b. audible sound has a higher frequency

c. ultrasound has a higher frequency

d. ultrasound waves are ionizing

c.

A decrease in the thickness of a piezoelectric element will result in

a. a greater pulse duration

b. an increase in the propagation speed

c. a decrease in the quality factor if the bandwidth decreases

d. an increase in the frequency of the transducer

d.

The resonant frequency of a pulsed-wave ultrasound transducer is dependent on

a. damping

b. the backing material

c. the thickness of the piezoelectric element and the speed of sound through the piezoelectric element

d. the amplitude of the voltage applied to the piezoelectric element

c.

The image is brighter at the level of the focal zone. Which of the following controls is best to correct this?

a. overall gain

b. TGC

c. acoustic power

d. PRF

b.

If the frequency is doubled,

a. the duty factor will increase

b. the period will double

c. the wavelength will double

d. the wavelength will be one-half

d.

The typical range of pulse repetition frequencies in a pulse-echo ultrasound system is

a. 2,000 Hz to 20,000 Hz

b. 20 MHz to 200 MHz

c. 20,000 Hz to 200,000 Hz

d. 1,000 Hz to 2,000 Hz

d.

If the number of cycles in a pulse is reduced,

a. the pulse repetition frequency is automatically reduced

b. the spatial pulse length increases

c. the pulse duration is reduced which results in a lower duty factor

d. the bandwidth is decreased and the quality factor is increased

c.

The minimum reflector separation required to produce separate echoes is

a. the spatial resolution of the ultrasound system

b. the temporal resolution

c. the attenuation coefficient

d. the total attentuation

a.

As the frequency of sound increases,

a. the amount of scatter is increased

b. the attenuation decreases

c. the amount of scatter decreases

d. the penetration increases

a.

Which of the following transducers provides the maximum penetration?

a. 10.0 MHz

b. 7.5 MHz

c. 2.25 MHz

d. 3.5 MHz

c.

The average attenuation of ultrasound energy in the patient is approximately

a. 2.0 dB per cm per MHz

b. 10.0 dB per cm per MHz

c. 5. dB per cm per MHz

d. 0.7 dB per cm per MHz

d.

If sound from a 3 MHz transducer has 3 dB of attenuation after traveling through 2 cm of tissue, what is the amount of attenuation of sound from a 5 MHz transducer after traveling through 1 cm of the same tissue?

a. 5 dB

b. 1 dB

c. 2 dB

d. 2.5 dB

d.

The half-value layer or the half-intensity-depth

a. is the depth where the intensity is 50% of the originally transmitted intensity

b. increases as the frequency of the transmitter increases

c. is the range of frequencies contained in an ultrasound pulse

d. is the attenuation coefficient in tissue

a.

The speed of ultrasound in soft tissue is closest to

a. 1.54 mm/sec

b. 1540 km/sec

c. 1540 mm/sec

d. 1540 m/s

d.

Ultrasound energy is traveling through the same medium. If the frequency is doubled, the propagation speed is

a. quartered

b. doubled

c. halved

d. unchanged

d.

The reason most ultrasound systems are calibrated at 1540 meters per second is because

a. 1540 meters per second is the average speed of sound encountered in the patient

b. 1540 meters per second is the maximum speed of sound encountered in a patient

c. 1540 meters per second is the speed of sound in muscle

d. 1540 meters per second is the maximum speed of sound in a patient

a.

The propagation speed is highest in

a. bone

b. tissue

c. fat

d. muscle

a.

The redirection of sound energy in many directions as a result of a rough boundary between two media is

a. shadowing

b. specular reflection

c. through-transmission

d. scattering

d.

The density is the same in materials A and B, but the speed of sound in material B is 10% greater than the speed of sound in material A.

a. The acoustic impedance in B is 10% greater than the acoustic impedance in A

b. The sound velocity in A is 10% higher than the propagation speed in B

c. The acoustic impedance in A is equal to the acoustic impedance in B

d. The acoustic impedance in A is 10% higher than the acoustic impedance in B

a.

Matching layers in a transducer

a. improve axial resolution

b. provide damping

c. determine the operating frequency

d. provide greater efficiency of sound transmission from the transducer to the patient

d.

The acoustic impedance of a matching layer in a transducer should have a value

a. between the acoustic impedance of the piezoelectric element and the acoustic impedance of tissue

b. lower than the acoustic impedance of tissue

c. greater than the acoustic impedance of the piezoelectric element

d. equal to the acoustic impedance of the piezoelectric element

a.

The prefix micro- represents the mathematical value

a. 10 to the 6th power

b. 10 to the negative 6th power

c. 10 to the third power

d. 10 to the negative third power

b.

The representation for volume is

a. m

b. cm

c. cm squared

d. cm cubed

d.

If the amplitude is decreased by 50%, what is the corresponding change in power?

a. -6 dB

b. 3 dB

c. -3 dB

d. 0 dB

a.

If the relative output power of an ultrasound instrument is calibrated in decibels and the operator increases the output by 20 dB. the beam intensity is increased by

a. twenty times

b. fiver percent

c. one hundred times

d. one million times

c.

A decrease in power or intensity by a factor of 2 represents a change of

a. -3 dB

b. -50 dB

c. -6 dB

d. 3 B

a.

The Power control on an ultrasound system is set at maximum. The display indicates PWR= 0 dB. If this Power control is used to reduce the intensity by one-half, the display will indicate PWR=

a. 2 dB

b. 0 dB

c. -3 dB

d. -6 dB

c.

Sound power is measured in units of

a. dB/cm

b. mW/cm

c. Watts

d. W/dB

c.

Which one of the following statements is true about a single pulse of ultrasound from a transducer?

a. It contains a range of frequencies

b. It contains sound at the resonant frequency of the transducer only

c. The shorter the pulse, the narrower the bandwidth

d. Sound energy is continuously transmitted

a.

Lateral resolution is determined mainly by

a. damping

b. beam diameter

c. pulse duration

d. spatial pulse length

b.

Which one of the following describes Snell's Law?

a. Law that describes the angle of transmitted beam

b. Law tat describes the impedance of two media

c. Law that describes the intensity of a reflected beam

d. Law that says you have to buckle up

a.

For a real time image to be flicker-free, the minimum image frame rate should be at least

a. 15 Hz

b. 1000 Hz

c. 1 Hz

d. 100 Hz

a.

In real time imaging the transmitted ultrasound beam is not continuously generated, but is pulsed. Approximately what fraction of time is the transducer actively generating sound waves?

a. 99%

b. 50%

c. 10%

d. 0.1%

d.

If the real time frame rate is increased and the lines per frame are unchanged, what else must happen?

a. imaging depth increases

b. transducer frequency increases

c. the pulse repetition frequency decreases

d. imaging depth decreases

d.

If the line density changes but the imaging depth remains the same, what else must change?

a. frame rate

b. pulse repetition period

c. pulse repetition frequency

d. resolution

a.

If the imaging depth is increased and the sector angle and line density remain the same,

a. the PRF increases

b. the frame rate decreases

c. the PRP decreases

d. the frame rate increases

b.

What principles states that sound is generated from the transducer as wavelets?

a. Snell's

b. Huygen's

c. Kremkau's

d. Bernoulli's

b.

What control should be used to correct the image to the right?

a. Increase the spectral gain

b. Raise the baseline

c. Lower the baseline

d. Increase the PRF

d.

Which transducer produces the image shape shown to the right?

a. flat linear array

b. phased array

c. curvilinear array

d. linear array

c.

Dynamic focusing is possible

a. only with transducers with frequencies above 5 MHz

b. only with transducer arrays

c. the two-element CW Doppler probes

d. with single piezoelectric elements

b.

With phased array transducers, the transmitted sound beam is swept by

a. mechanically sweeping the piezoelectric elements

b. mechanically rotating the piezoelectric elements

c. varying the timing of pulses to the individual piezoelectric elements

d. varying the frequency of pulses to the individual piezoelectric elements

c.

Which pulsing pattern provides a non-steered beam that is focused?

a. A

b. B

c. C

d. D

e. E

a.

A 1.5D transducer has what ability?

a. Electronically focus in the elevational plane

b. Produce a 3D image

c. Dynamic aperature

d. Color Doppler imaging

a.

Parenchyma appears on ultrasound as a pattern of gray dots. This interference pattern is a result of

a. specular reflectors

b. harmonic signals

c. acoustic speckle

d. large border reflectors

c.

Which of the following frequencies is in the "ultrasound" range?

a. 15 MHz

b. 15 kHz

c. 15 MHz

d. 17,000 MHz

c.

Which of the following has the highest relative attenuation?

a. bone

b. air

c. liver

d. blood

b.

A small (relative to the wavelength) reflector is said to ______________ an incident sound beam

a. focus

b. speculate

c. scatter

d. amplify

c.

The fundamental operating principle of medical ultrasound transducers is:

a. Snell's law

b. magnetostrictive effect

c. impedance effect

d. piezoelectric effect

d.

The axial resolution is primarily determined by:

a. spatial pulse length

b. transducer diameter

c. acoustic impedance

d. density

a.

Increasing frequency:

a. improves spatial resolution

b. increases penetration

c. increases the wavelength

d. increases the period

a.

Diagnostic ultrasound frequency range is:

a. 2 to 10 mHz

b. 2 to 10 kHz

c. 2 to 15 MHz

d. 5 to 15 kHz

c.

Pulse duration is the _________ it takes for one __________ to occur

a. distance; pulse

b. distance; cycle

c. time; pulse

d. time; cycle

c.

Spatial pulse length equals the number of cycles in a pulse multiplied by:

a. period

b. impedance

c. beam width

d. wavelength

d.

The attenuation of 5 MHz ultrasound in 4 cm of soft tissue is:

a. 2.5 dB/cm

b. 10 dB

c. 2.5 MHz/cm

d. 2 cm

b.

Which of the following quantities vary most with distance from the transducer?

a. axial resolution

b. lateral resolution

c. freqency

d. period

b.

The lateral resolution of an ultrasound system depends on:

a. the aperature

b. the transducer frequency

c. both a and b

d. none of the above

c.

Which of the following is a characteristic of the medium through which a sound is propagating?

a. impedance

b. intensity

c. amplitude

d. frequency

a.

Attenuation along a sound path is a decrease in:

a. frequency

b. amplitude

c. wavelength

d. propagation speed

b.

An unfocused, single-element disc transducer that is 13mm in diameter has a diameter at the focal zone of:

a. 13 mm

b. 6.5 mm

c. 26 mm

d. cannot be determined

b.

Which of the following has time represented on the X-axis?

a. B-mode

b. X-mode

c. M mode

d. A mode

c.

Which of the following produces a rectangular format?

a. curvilinear sequenced array

b. convex array

c. phased array

d. linear sequenced array

d.

The piezoelectric effect describes how __________ is converted into ___________ by a ___________.

a. electricity; image; display

b. ultrasound; heat; tissue

c. incident sound; reflected sound; boundary

d. ultrasound; electricity; transducer

d.

As frequency is increased:

a. a three-cycle ultrasound pulse decreases in length

b. wavelength increases

c. attenuation decreases

d. propagation speed increases

a.

Focusing

a. Improves lateral resolution

b. Improves axial resolution

c. Increases beam width in the focal zone

d. Increases duty factor

a.

The term rarefaction describes a zone of ____________ in a medium traversed by the wave.

a. increased velocity

b. decreased pressure

c. decreased flow

d. increased amplitude

b.

A longitudinal wave is characterized by _____________.

a. the ability of the sound wave to penetrate 5 cm of tissue

b. frequency of vibration greater than 1 MHz

c. acoustic velocity equals 1,540 m/s

d. particle motion in same direction as the direction of wave propagation

d.

Which prefix equals 10 to the negative third?

a. micro-

b. milli-

c. centi-

d. mega-

b.

Which of the following is a characteristic(s) of non-specular reflectors?

a. they provide the internal texture of organs in B-mode imaging

b. they occur at interfaces with large dimensions relative to the wavelength

c. they are highly angle dependent

d. they never return sound energy back to the transducer

a.

Relative sound intensity based on a logarithmic scale is expressed typically in units of:

a. rayl

b. decibel

c. Hertz

d. Curie

b.

Pulsed-wave operation is necessary for B-mode imaging because:

a. the transducer becomes too hot to handle if continuous wave is used

b. the crystal would break with continuously produced sound waves

c. the depth to the reflector can be determined

d. improved temporal resolution

c.

Which Doppler function controls how many waveforms are displayed on the image at one time?

a. sweep speed

b. gate size

c. scale

d. spectral gain

a.

If the number of lines per frame is kept constant, but the pulse repetition frequency is doubled, what is the effect on the maximum frame rate?

a. doubled

b. halved

c. quadrupled

d. unchanged

a.

Looking at the image to the right, what type of image mode was used?

a. A-mode

b. B-mode

c. M-mode

d. Amplitude mode

c.

Which of the following terms does not belong with the others?

a. Increased depth of view

b. Decreased duty factor

c. Increased pulse repetition period

d. Decreased spatial pulse length

d.

If the power of a wave is halved, the intensity ___________ its original value.

a. Is reduced to one-half its original value

b. Is reduced to one-fourth its original value

c. Is the same as the original intensity and does not change

d. Is double its original value

a.

Which of the following will create the fastest speed of sound?

a. High density, high stiffness

b. Low density, high stiffness

c. High density, low stiffness

d. Low density, low stiffness

b.

Longitudinal resolution is also called

a. Axial

b. Azimuthal

c. Lateral

d. Transverse

a.

Which of the following is the best lateral resolution?

a. 15 mm

b. 6 mm

c. 6 cm

d. 2 cm

b.

An increase in the diameter of a transducer results in a(n) ______________ of the near zone length

a. increase

b. decrease

c. no change

a.

To create a transducer with less divergence in the far field, you would use

a. a transducer with a larger diameter

b. a transducer with a small diameter

c. a transducer with a shorter spatial pulse length

d. a transducer with a shorter pulse duration

a.

Which of the following is a true statement?

a. Color Doppler has the highest frame rate of all the modes of imaging

b. Most ultrasound machines have the ability to detect the propagation speed through which the sound is traveling

c. Most ultrasound machines have better lateral resolution than axial resolution

d. Most ultrasound machines have better axial resolution than lateral resolution

d.

Which transducer has the best axial resolution?

a. 2 cycles/pulse, 4 MHz

b. 4 cycles/pulse, 4 MHz

c. 4 cycles/pulse, 2 MHz

d. 2 cycles/pulse, 2 MHz

a.

What is the primary disadvantage of multiple focal zones along each scan line of a two-dimensional image?

a. Improved temporal resolution

b. Decreased temporal resolution

c. Improved axial resolution

d. Improved lateral resolution

b.

Which of the following will improve a system's temporal resolution

a. Increased sector angle

b. Increased line density

c. Increased PRF

d. Increased frequency

c.

Which of the following transducers fire the elements in groups?

a. linear sequenced array

b. phased array

c. mechanical sector

d. static B-scanner

a.

Which of the following is true about PRF?

a. PRF increases as depth increases

b. PRF increases as pulse repetition period increases

c. PRF increases as pulse duration increases

d. PRF inceases as depth decreases

d.

What is the component of an ultrasound system that is made rout of lead zirconate titanate?

a. Transducer's matching layer

b. Transducer's active element

c. Transducer's damping material

d. Insulation

b.

Two ultrasound systems produce pulses. One pulse is 0.4 microseconds in duration and the other is 0.2 microseconds. Which pulse is most likely to produce the best radial resolution?

a. 0.4 microsecond system

b. 0.2 microsecond system

c. They are not the same

d. Cannot be determined

b.

Which of the following is proportional to the square of the amplitude?

a. Period

b. Impedance

c. Power

d. Frequency

c.

Which of the following will produce a transducer with a high Q-factor?

a. Heavily damped transducer

b. Pulsed-wave operation

c. Wide bandwidth transducer

d. Continuous-wave transducer

d.

For perpendicular incidence, if the impedances of the media are the same, there will be no

a. Reflection

b. Refraction

c. Inflection

d. Transmission

a.