SPI Practice

The matching layer's optimal thickness is: _________ wavelength

1/4

The near zone length of an unfocused single element transducer is 8 cm and the diameter of the crystal is 1 cm. What is the lateral resolution at a depth of 8 cm in soft tissue?

5 mm

The period for a 2 MHz transducer is 0.5: a. nanoseconds b. milliseconds c. microseconds d. seconds

c. microseconds

The duplication of the doppler signal on the opposite side of the baseline is called: a. aliasing b. multipath c. mirroring d. reverberation

c. mirroring

The device that can measure acoustic pressure at specific locations within the ultrasound beam is called

hydrophone probe

In vitro means:

in a test tube

All of the following may be used to express the speed of sound in soft tissue except: a. 15400 cm b. 1540 m/s c. 1.54 km/s d. 1.54 mm/microsecond

a. 15400 cm

For which of the following insonification angles will the doppler shift be the greatest? a. 180 b. 45 c. 90 d. 10

a. 180

Dedicated continuous wave Doppler transducers have a. 2 crystals b. low sensitivity c. low quality factor d. thick damping material

a. 2 crystals

What is the typical range of Doppler shifts found in diagnostic imaging applications? a. 20 Hz to 20 KHz b. 2 MHz to 20 MHz c. 20 KHz to 200 KHz

a. 20 Hz to 20 KHz

What is the pulse repetition period if the maximum depth is 1 cm in soft tissue?

13 microseconds

What is the degree of refraction if there is an incident angle of 60 degrees and a transmission angle of 80 degrees?

20

If the Pulse Repetition Period is 260 µsec, the maximum depth setting in soft tissue is:

200 mm (20 cm)

Laminar flow is disrupted and turbulence occurs when the Reynold's number exceeds

2000

Turbulent flow is possible when the blood flow exceeds what Reynolds number?

2000

If an ultrasound wavelength is 0.5 mm in soft tissue, the operating frequency will be:

3.0 MHz

The standard frame rate is:

30 Hz

How many shades of gray may be stored in a 5-bit memory?

32

If the angle of incidence is 25º and media propagation speeds are 1.4 mm/μsec for medium one and 1.8 mm/μsec for medium two. What is the angle of transmission?

32 degrees

Power is set at 40 dB. If the power is reduced by one half, what will the new power in dB be?

37

The total attenuation in soft tissue for a 2 MHz transducer at 3 cm is:

3db

In ultrasound imaging, the portion of the sound beam used to generate the image is the: a. reflected portion b. refracted portion c. backscattered portion d. absorbed portion

a. reflected portion

There is normal incidence. The acoustic impedance in medium 1 is 1.3 Megarayls and the acoustic impedance in medium 2 is 1.3 Megarayls. There will be no: a. refraction, reflection b. reverberation c. transmission d. attenuation

a. refraction, reflection

Grey scale display of ultrasonic images was made possible by: a. scan converters b. oscilloscopes c. electron guns d. phased array transducers

a. scan converters

Elevation resolution is affected by which of the following? a. slice thickness b. pulse duration c. spatial pulse length d. beam width

a. slice thickness

Transducer frequency is dependent upon which of the following? a. the source of sound b. characteristics of the medium c. velocity of sound in soft tissue d. all of the above

a. the source of sound

Increasing the number of bits per pixel will improve: a. axial resolution b. contrast resolution c. temporal resolution d. lateral resolution

b. contrast resolution

Which of the following would give the deepest focus? a. D= 1 mm, f = 2 MHz b. D= 2 mm, f = 2 MHz c. D=2 mm, f = 2 MHz d. D = 1 mm, f = 10 MHz

b. d= 2mm, f = 10 MHz

To improve temporal resolution in viewing blood flow with color doppler imaging, one can: a. decrease the nyquist limit b. decrease the doppler packet size c. increase the maximum depth d. increase the system gain

b. decrease the doppler packet size

The amount of space measured from one end of an object to the other end of the object is the: a. area b. distance c. circumference d. radius

b. distance

The range of frequencies used in clinical ultrasound imaging is: a. 20 KHz to 2 MHz b. 20 Hz to 20 KHz c. 2 MHz to 12 MHz d. 2 MHz to 200 MHz

c. 2 MHz to 12 MHz

The frequencies generally used for diagnostic ultrasound are: a. 1 MHZ to 100 MHZ b. 1,000 Hz to 12,000 Hz c. 2,000,000 Hz to 12 MHz d. 20 Hz to 20 kHz

c. 2,000,000 Hz to 12 MHz

If the propagation speed of sound in PZT is 4.0 mm per microsecond, crystal thickness is 0.5 mm and the frequency of the drive voltage is 4 MHz. What would be the CW operating frequency of that crystal? a. 8 MHz b. 5 MHz c. 4 MHz d. 12 MHz

c. 4 MHz

If the transmit power level is unchanged, which one of the following frequencies will be associated with the lowest mechanical index (MI)? a. 3.5 MHz b. 2.5 MHz c. 8 MHz d. 5 MHz

c. 8 MHz

What percentage of beam is transmitted at a muscle - soft tissue interface? a. 100 b. 1 c. 99 d. 50

c. 99

Which one of the following test objects does not have the attenuation properties of soft tissue? a. Doppler phantom / flow system b. beam profile / slice thickness c. AIUM 100 mm phantom d. multipurpose tissue equivalent phantom

c. AIUM 100 mm phantom

Which of the following modalities has the worst temporal resolution? a. 2D imaging b. PW Doppler c. Color Doppler d. CW Doppler

c. Color Doppler

The principle that explains why piezoelectric elements are able to form a sound beam with a near field, natural focus and a far field: a. doppler b. Bernoulli c. Huygen's d. Poiseuille's

c. Huygen's

What is the correct descending (largest to smallest) order for : a. Micro, Milli, Kilo, Mega b. Mega, Micro, Milli, Kilo c. Mega, Kilo, Milli, Micro d. Kilo, Micro, Mega, Milli

c. Mega, Kilo, Milli, Micro

Which modality has the highest intensity levels? a. all are equal b. M mode c. PW / Color Doppler d. B mode

c. PW / Color Doppler

Axial resolution is determined by: a. PRF b. PRP c. SPL d. Beam Width

c. SPL

An artifact that would least likely produce a pseudo-mass is: a. ghost artifact b. a mirror image artifact c. a comet tail artifact d. a multipath artifact

c. a comet tail artifact

A 5 MHz transducer used in a pulse-echo system will generally produce: a. a wide band of frequencies above 5 MHz b. a narrow band of frequencies centered at 5 MHz c. a wide band of frequencies centered at 5 MHz d. frequencies only at 5 MHZ

c. a wide band of frequencies centered at 5 MHz

What could be used to successfully image shallow structures away from the dead zone? a. warm coupling gel b. a lower frequency transducer c. an acoustic standoff pad d. a linear array transducer

c. an acoustic standoff pad

If one element of a linear sequenced array fails, the display will demonstrate: a. a blank display b. an echo free horizontal line c. an echo free vertical line

c. an echo free vertical line

Dynamic focusing is: a. made possible by acoustic lens b. often used in single element systems c. made possible by array based systems d. not possible

c. made possible by array based systems

If a wave needs a medium to propagate it is a(n) _____________ wave? a. longitudinal b. transverse c. mechanical d. electromagnetic

c. mechanical

The mechanical Index (MI) is directly proportional to: a. frequency b. gain in dB c. peak negative pressure d. microbubble size

c. peak negative pressure

Which piezoelectric effect does the transducer utilize on reception? a. reverse piezoelectric effect b. cannot be determined c. piezoelectric effect d. both

c. piezoelectric effect

Imaging ultrasound uses __________ ultrasound to obtain images of structures. a. color b. harmonics c. pulsed wave d. continuous wave

c. pulsed wave

Which one of the following describes the relationship between frequency and period? a. unrelated b. proportional c. reciprocal d. logarithmically related

c. reciprocal

As image depth increases, PRF:

decreases

Propagation velocity _________ with density and _________ with compresibility

decreases decreases

As the number of cycles in a pulse increases, the pulse duration increases, the bandwidth ____________ and the axial resolution ________________________.

decreases worsens

The process of rectification and smoothing of radiofrequency echo signals is called:

demodulation

Pulse repetition period in soft tissue is equal to:

depth x 13 usec/cm

Acoustic speckle is caused by

destructive and constructive interference

Specificity is a statistical parameter that is a measure of a test's ability to:

detect the absence of disease when no disease exists

Sensitivity is a statistical parameter that is a measure of a test's ability to:

detect the presence of disease when disease exists

What type of reflector is large and jagged in comparison to the wavelength?

diffuse

A perimeter measurement is a measure of:

distance

For pulsed wave transducers, thin elements produce _________ frequencies

high frequencies

If the RBC's are moving towards the transducer, the received frequency is

higher than the transmitted frequency

The formula for duty factor is:

pulse duration / pulse repetition period

The number of ultrasound pulses emitted per second is:

pulse repetition frequency

The most common piezoelectric crystal found in nature is:

quartz

A reflection will be placed at the correct depth because the ultrasound machine will utilize the ______ equation:

range

Transducer bandwidth is best described as:

range of frequencies above and below the operating frequency

A region of low density is called?

rarefaction

Circular waves that travel across the surface when a rock is tossed into the water are called:

rayleigh waves

How does a shorter pulse duration affect the bandwidth

shorter pulse duration = increased bandwidth

Weak reflections created by beams outside the main beam

side lobes

The artifact where a fluid filled cyst may be filled in with debris:

slice thickness

To improve spatial resolution in two-dimensional imaging, the Ultrasound system should be evaluated for

slice thickness

What gives the tissue mimicking gel attenuation properties similar to that of soft tissue?

small embedded scatterers

What imaging assumption is violated when a comet tail artifact occurs?

sound travels directly to a reflector and back

Pulse duration is determined by the:

source

Axial resolution is directly related to:

spatial pulse length and pulse duration

What type of reflector is large and smooth in comparison to the wavelength?

specular

In order to calculate distance to a reflector, the ___________ and the pulse round trip must be know.

speed

What is measured using the continuity equation?

stenotic orifice area

The speed of sound is greater in bone than air because bone is more:

stiff

Dividing a normal crystal into many smaller elements is termed:

subdicing

To evaluate rapidly moving structures, good __________ resolution is necessary

temporal

The relationship between velocity of flow across an obstruction and the pressure gradient is described by:

the Bernoulli equation

The changes in frequency and wavelength due to moving reflectors is called:

the Doppler effect

The term used in color Doppler to describe turbulent flow:

variant

The time for one pulse:

PD

The nyquist limit is equal to:

PRF / 2

If the spatial pulse length is 6 mm, axial resolution is:

0.3 cm

The fraction of time an ultrasound machine spends emitting pulses is called:

DF

The unit of Power used in ultrasound imaging is:

Watt

Autocorrelation predicts the: a. mean velocity b. modal velocity c. peak velocity

a. mean velocity

A binary digit is called a:

bit

The unit for attenuation coefficient is:

dB/cm

A continuous wave transducer is 12 mm, the sound beam width at two near zone length is:

12 mm

Another name for the "Reject" control is:

threshold

If the power is decreased by a factor of two and all beam dimensions remain the same, the intensity is changed by:

-3 dB

If the duration of an ultrasound pulse is one microsecond, and the PRP is 1000 microseconds, then the duty factor is:

0.001

If the frequency is 5 MHz the period is:

0.2 microseconds

If the spatial pulse length is 10 mm, axial resolution is:

0.5 cm

The attenuation coefficient for soft tissue is approximately:

0.5 dB/cm/MHz

The maximum value for the duty factor in pulsed wave ultrasound is:

1%

The percentage of time spent transmitting in clinical imaging is approximately:

1%

If a receiver had a dynamic range of 60 dB, how many different echo amplitudes is it able to process?

1000

If the gain of an amplifier is 18 dB, what will the new gain setting be if the gain setting is reduced by one half?

15 dB

The propagation speed of sound in soft tissue is:

1540 m/s

The propagation speed of the AIUM 100 test object is?

1540 m/s

A sound wave leaves its source and travels through air. The speed of sound in air is 330 meters per second. One second later, an echo returns to the source. At what distance from the source is the reflector that produced the echo?

165 meters

The number of crystals in a continuous wave transducer:

2

If a transducer moves toward a target at 1 m/sec and a target moves toward the transducer at 1 m/sec, the velocity registered by the Doppler effect would be:

2 m/s

The spatial pulse length is 4 mm. The axial resolution is:

2 mm

If the spatial pulse length is 5 mm, then the axial resolution is:

2.5 mm

According to the AIUM, at what in situ tissue temperature is there danger to a fetus?

41 degrees celcius

If an intensity level expressed as 50 dB is reduced to one fourth of its value, the final intensity level would be:

44 dB

If an intensity level expressed at 50 dB is reduced by 50%, the final intensity level is:

47 dB

A sound wave with a 4 MHz frequency travels 3 cm in soft tissue. What is the total attenuation that the sound beam experiences? a. 6 dB b. 4 dB/cm c. 12 dB d. 20 dB

6 dB

In soft tissue, which of the following represents at 75% decrease in intensity?

6 dB

A continuous wave unfocused transducer is 12 mm. The sound beam width at one near zone length is:

6 mm

If particle displacement caused by an acoustic wave is +/- 6 nm, the amplitude is:

6 nm

If the amplitude of a sound wave is increased 1,000 times, what is the change in decibels?

60

A 6 bit memory can represent how many shades of gray?

64

If an intensity level expressed at 50 dB and the final intensity level is 44 dB, how much intensity is lost?

75%

Image depth x number of foci x lines per frame rate can not exceed:

77,000

No doppler shift is recorded when the insonification angle is:

90 degrees

With pulsed ultrasound the transducer is listening for echoes at least _________% of the time.

99

What mode displays spikes of amplitude?

A mode

Which of the following is an appropriate unit of acoustic intensity? A. Watt/cm² B. mm Hg C. Newton D. mVolt

A. Watt/cm²

Which of the following equations best describes the relationship between crystal thickness and operating frequency? A. f = c/ 2w B. Z = ρ x c C. T = 1/ f D. λ = c/f

A. f = c/ 2w

Which of the following equations best describes the relationship between wavelength, propagation speed, and frequency? A. f = c/λ B. T = 1/ f C. f = c/ 2w D. Z = ρ x c

A. f = c/λ

A __________ is a b-mode operation that provides a cross section of the region of interest as the sound beam sweeps through the region of interest

B scan

Which of the following increases the strength of all returning reflections regardless of depth: a. TGC b. Gain c. Demodulation d. Reject

B. Gain

Which one of the following frequencies is infrasonic? a. 20 KHz b. 500 Hz c. 14 Hz 3 MHz

c. 14 Hz

What effect will an increase in mediums elasticity have on the speed of sound?

decrease

Which of the following is not an appropriate unit of pressure? A. mm Hg B. Torr C. Watt/cm² D. Pascal

C. Watt/cm²

The type of Doppler system that uses 2 crystals

CW

Range ambiguity is a limitation of

CW doppler

Which of the following units are used to measure intensity in ultrasound application? A. watts/m2 B. mW/cm C. watts/m D. mW/cm2

D. mW/cm2

What is the definition of Acoustic Pressure?

Force per unit area of the sound beam

The resistivity index is also known as:

Index of Pourcelot

The C-mode is used to display:

PW Doppler blood flow velocity information

The artifact which displays two structures that lie perpendicular to the sound beam as one is:

Lateral resolution

PACS systems are digital systems used for

Picture archiving and communication

Which equation describes the relationship between flow rate and the parameters of pressure gradient, vessel radius and viscosity of blood?

Poiseuille

Rouleau flow is described as:

RBC aggregation

The unit of acoustic Impedance used in the metric system:

Rayl

In a cathode ray tube (CRT), echoes are placed in their proper position by deflecting the electron beam through the

X and Y deflection plates

The symbol for acoustic impedance is:

Z

color flow imaging shows turbulence as:

a mosaic of colors

PW doppler obtains doppler shift information by:

a sample gate

Which of the following Doppler angles gives the greater Doppler shift? a. 0 b. 30 c. 90 d. 60

a. 0

Which one of the following frequencies will be associated with the shortest wavelength? a. 10 MHz b. 6000 Hz c. 2.5 MHz d. 100 kHz

a. 10 MHz

The assumed propagation velocity of sound in soft tissue is: a. 154,000 cm/sec b. 1540 cm/sec c. 1450 cm/sec d. 1.54 m/sec

a. 154,000 cm/sec

The propagation speed of sound in soft tissue is: a. 1540 m/s b. 1540 km/s c. 1.54 m/s d. 1.54 nm/s

a. 1540 m/s

Which one of the following does not affect Color frame rate? a. packet size b. color gain c. color box width d. color box depth

b. color gain

At what angle between the sound beam and the direction of motion with the doppler shift be a minimum? a. 90 degrees b. 60 degrees c. 0 degrees d. 180 degrees

a. 90 degrees

The lowest measured intensity is: a. SATA b. SPTA c. SPTP d. SATP

a. SATA

The highest measured intensity is: a. SPTP b. SATA c. SPTA d. SATP

a. SPTP

Temporal resolution is related to all of the following except: a. TGC profile b. more lines per frame c. imaging at shallower depths

a. TGC profile

Switching to a higher frequency transducer to quantify a regurgitant jet or stenotic flow will result in: a. a higher doppler frequency shift b. a different velocity measurement c. the same doppler frequency shift d. a lower doppler frequency shift

a. a higher doppler frequency shift

The product of tissue density and speed of sound in tissue is known as: a. acoustic impedance b. attenuation coefficient c. bulk modulus d. reflectivity

a. acoustic impedance

Which one of the following is not an acoustic variable? a. acoustic intensity b. density c. temperature d. acoustic pressure

a. acoustic intensity

The portion of the ultrasound beam used to generate doppler information is the: a. backscattered portion b. absorbed portion c. reflected portion d. transmitted portion

a. backscattered portion

The doppler shift in frequency is directly proportional to: a. blood flow velocity b. size of the scatterer c. speaker volume control d. velocity of sound in the medium

a. blood flow velocity

Ultrasound travels fastest through which of the following? a. bone b. air c. lung d. soft tissue

a. bone

An increase in the speed of sound will occur if there is an increase in: a. bulk modulus b. compresibility c. elasticity

a. bulk modulus

Which of the following improves frame rate thereby improving temporal resolution? a. decrease line density b. increases the number of foci c. increase color packet size d. increase the display width

a. decrease line density

The length of the near field can be increased by increasing transducer: a. diameter b. sensitivity c. damping d. bandwidth

a. diameter

Changes in the doppler shift frequencies within a color flow image sample site appear in the image as: a. different colors and/or levels of saturation b. different hues c. different levels of color saturation d. nothing

a. different levels of color saturation

Which of the following factors does NOT affect spatial resolution in the displayed image? a. display format b. matrix size c. number of display raster lines d. pixel density

a. display format

Scattering of an ultrasound beam is necessary for: a. doppler shift detection b. b-scan image formation c. focusing d. reducing attenuation

a. doppler shift detection

If the frequency is reduced by a factor of two, the wavelength will: a. double b. increase by a factor of four c. remain the same d. become shorter by 1/2 e. become shorter by 1/4

a. double

The propagation speed of sound at any frequency is determined by: a. elastic properties of the medium b. the duration of a cycle of compressions and rarefactions c. the source of sound d. the intensity of the sound signal

a. elastic properties of the medium

In doppler spectral analysis, which of the following is used to separate complex frequency shifts into their individual components? a. fast fourier transform b. autocorrelation c. bernoulli principle d. velocity time integral

a. fast fourier transform

How does a slice thickness artifact commonly appear? a. filling in of cystic and anechoic structures b. strong multiple linear echoes c. absence of reflectors d. a mirror image of the reflector

a. filling in of cystic and anechoic structures

All of the following determine the percentage of reflection except: a. frequency b. acoustic impedance c. acoustic impedance mismatch d. angle of incidence

a. frequency

Which one of the following cannot be measured by the AIUM 100 mm Phantom? a. gray scale b. axial resolution c. minimum sensitivity d. dead zone

a. gray scale

The wall filters in doppler are ___________ filters which reduce the __________ of __________ frequency signals a. high pass, amplitude, low b. low pass, velocity, high c. low pass, amplitude, low d. high pass, velocity, high

a. high pass, amplitude, low

A way to decrease period, pulse duration, wavelength, spatial pulse length, and improve axial resolution is: a. increase frequency b. decrease PRF c. increase spatial pulse length d. increase pulse duration

a. increase frequency

Using a backing material shortens the SPL and: a. increases transducer bandwidth and decreases sensitivity b. decreases transducer bandwidth c. improves sensitivity d. increases transducer bandwidth and improves sensitivity

a. increases transducer bandwidth and decreases sensitivity

Preprocessing occurs before: a. memory b. transducer acquisition c. patient arrival d. analog to digital conversion

a. memory

All of the following will effect propagation speed except: a. period b. density c. bulk modulus d. stiffness

a. period

Which of the following epidemiologic studies is considered most likely to produce meaningful results: a. prospective and randomized b. prospective and mechanistic c. retrospective and prospective d. retrospective and empirical

a. prospective and randomized

A sound wave strikes a large smooth interface between two media orthogonally. The acoustic impedances of the media are identical but their densities are different. Which of the following will occur? a. total transmission b. refraction c. reflection d. scattering

a. total transmission

Which of the following has the greatest effect on the near zone length? a. transducer diameter b. frequency c. period d. matching layer

a. transducer diameter

Attenuation of the intensity of sound in soft tissue is determined by: a. transducer frequency and path length b. propagation speed and refraction c. density and stiffness of the medium d. transducer frequency and PRF

a. transducer frequency and path length

Which bioeffect is associated with the decomposition of water into free radicals? a. transient cavitation b. absorption c. stable cavitation d. microstreaming

a. transient cavitation

Vertical depth calibration is measured a. using the system's own electronic calipers b. in the dead zone c. using an acoustic standoff pad d. using a slick thickness phantom

a. using the system's own electronic calipers

A "bin" in doppler spectral analysis represents a: a. velocity range b. pixel c. sample volume d. group

a. velocity range

Clinical imaging transducers have: a. wide bandwidth, low Q factor b. wide bandwidth, high Q factor c. narrow bandwidth, low Q factor c. narrow bandwidth, high Q factor

a. wide bandwidth, low Q factor

A method used to unwrap a PW aliased signal is: a. zero baseline shift b. increase transmit frequency c. decreased PRF d. increase the sample gate size

a. zero baseline shift

A hydrophone is used to measure:

acoustic energy

The product of medium density and ultrasound propagation speed is known as:

acoustic impedance

The speed of sound in soft tissue multiplied by the density is equal to:

acoustic impedance

When receiving echoes, the piezoelectric crystal develops a voltage across its terminals which is proportional to the

acoustic pressure on the transducer face

An increase in the doppler transmit frequency may result in what artifact

aliasing

The overall gain control affects the image by varying the:

amplification of all echo signals equally

Which transducer type has ring shaped elements organized concentrically?

annular array

If 3000 cycles occur in 2 seconds, the frequency would be: a. 6000 Hz b. 1500 MHz c. 1.5 KHz d. 6 MHz

c. 1.5 KHz

What is used to reduce grating lobes?

apodization

Pressure is force per unit:

area

The conversion of sound energy into heat is called:

attenuation

The loss of sound intensity and amplitude is called:

attenuation

Time Gain Compensation (TGC) compensates for

attenuation

The technique used to process color doppler:

autocorrelation

A doppler spectrum below the baseline represents blood flow:

away from the transducer

The best type of resolution in clinical imaging is:

axial

The ability to resolve two structures lying parallel to the sound beams main axis is called:

axial resolution

At what angle between the sound beam and the direction of motion will the doppler shift be a maximum? a. 60 degrees b. 0 degrees c. 30 degrees d. 90 degrees

b. 0 degrees

Which of the following would be an example of a Rayleigh reflector if the wavelength is 0.5 mm? a. 10 mm b. 0.4 mm c. 1.0 mm d. 5mm

b. 0.4 mm

If a pulse consists of 4 cycles and the operating frequency is 5 MHz; what is the Pulse Duration? a. 1.25 sec b. 0.8 usec c. 20 msec d. 0.2 usec

b. 0.8 usec

How much energy will be reflected at a fat-muscle interface? a. 30% b. 1% c. 50% d. 99%

b. 1%

The average velocity of sound in soft tissue is equal to: a. 1450 m/sec b. 154000 cm/sec c. 1.56 mm/sec d. 1540 mm/usec

b. 154000 cm/sec

A average frame rate for conventional real-time ultrasound systems is about: a. 50 / min b. 30 Hz c. 80 Hz d. 20 KHz

b. 30 Hz

How far can ultrasound travel in air in 5 seconds? a. 331 m b. 5 sec x 331 m/sec = 1,655 m c. 5 sec x 1540 m/sec = 7700 m d. 1540 m

b. 5 sec X 331 m/s = 1,655 m

The principle that states all points on a wavefront can be treated as point sources producing secondary wavelets whose tangental surface predicts the new position of the wave over time is called: a. rayleigh's b. Huygen's c. Heisenburg d. Snell's

b. Huygen's

The ultrasound intensity often referred to in the AIUM statements on the thermal biological effects is the: a. SPPA b. SPTA c. SPTP d. SATA

b. SPTA

The spatial pulse length is equal to the number of cycles per pulse multiplied by the wavelength and does NOT depend on which of the following: a. frequency b. amplitude c. propagation velocity d. period

b. amplitude

Which of the following is not a potential mechanism for production of bioeffects? a. mechanical vibration b. apodization c. cavitation d. temperature elevation

b. apodization

Which of the following does not fall under preprocessing: a. rejection b. assignment of numbers to echoes c. transmit gain d. TGC

b. assignment of numbers to echoes

The amount of attenuation per centimeter is called: a. half intensity depth b. attenuation coefficient c. attenuation d. total attenuation

b. attenuation coefficient

Which resolution has the ability to resolve closely spaced structures which lie parallel to the sound beam? a. lateral b. axial c. contrast d. temporal

b. axial

Which one of the following is not a color flow Doppler artifact: a. aliasing b. blossoming c. mirror image d. ghosting

b. blossoming

Of the following choices, which is considered the most important for the sonographer to make with regard to bioeffects and safety? a. temperature of scanning room b. duration of the scan c. ambient light levels d. PRF

b. duration of the scan

Annular phased arrays, unlike linear phased arrays: a. can be used in Doppler systems b. electronically focus in two dimensions c. electronically focus in one dimension d. can be focused dynamically

b. electronically focus in two dimensions

Which of these terms best describes the empirical investigation of bioeffects? a. cause-effect b. exposure-response c. exposure-cure d. cause-response

b. exposure-response

To increase the depth of penetration the sonographer should decrease: a. receiver gain b. frequency c. transmit gain d. reject

b. frequency

To which of the following is Rayleigh scattering related? a. diameter of the transducer squared b. frequency raised to the 4th power c. half of the SPL d. half of the wavelength

b. frequency raised to the 4th power

The color that indicates flow variance: a. red b. green c. blue d. black

b. green

Shadowing is caused by ____________ and is the opposite of the ____________ artifact a. high attenuation, range b. high attenuation, enhancement c. low reflection, refraction d. low reflection, enhancement

b. high attenuation, enhancement

Total attenuation is directly related to: a. period b. image depth c. transducer type d. propagation speed

b. image depth

Which of the following occurs during inspiration? a. diaphragm rises b. increased flow from abdomen to thorax c. increased intrathoracic pressure d. decreased intra-abdominal pressure

b. increased flow from abdomen to thorax

In the Fraunhofer Zone of the ultrasound beam: a. intensity fluctuations occur b. intensity steadily fades with distance c. acoustic pressure is highest d. sound intensity is highest

b. intensities steadily fades with distance

The frequency of ultrasound: a. increases with density b. is determined by the pulser and/or the transducer c. changes with changes in the medium d. increases with stiffness

b. is determined by the pulser and/or the transducer

A unit used to measure blood flow is: a. mm Hg b. mL/min c. Poise d. Joule

b. mL/min

What type of transducer arranges the piezoelectric elements in rows and columns: a. vector b. matrix c. annular d. phased

b. matrix

Which of the following cannot be measured using a multipurpose tissue equivalent phantom? a. gray scale b. maximum velocity c. dead zone d. axial resolution

b. maximum velocity

In a Doppler ultrasound system, the Doppler shift is extracted from the transmitted and reflected frequencies in the: a. doppler shift detector b. mixer c. autocorrelator d. high pass filter

b. mixer

Ultrasound beam intensity is directly affected by: a. pulse repetition period b. output power c. overall gain d. time gain compensation

b. output power

Read magnification is performed during: a. pulse transmission b. postprocessing c. image storage d. preprocessing

b. post processing

Which of the following is not an acoustic variable: a. temperature b. propagation speed c. pressure d. density

b. propagation speed

The disadvantage of continuous wave Doppler: a. aliasing b. range ambiguity c. nyquist limit d. inherent sampling rate

b. range ambiguity

A preferred method to determine the minimum sensitivity of an ultrasound system is to adjust the: a. TGC b. receiver gain c. power output d. temperature of the scanning room

b. receiver gain

The preferred method to determine the minimum sensitivity of an ultrasound system is to adjust the: a. TGC b. receiver gain c. power output d. temperature of the scanning room

b. receiver gain

Which of the following does not occur with normal incidence? a. oblique b. refraction c. transmission d. reflection

b. refraction

To reduce spectral broadening, decrease: a. image depth b. sample gate size c. reject d. transmit frequency

b. sample gate size

The propagation speed is directly related to the mediums: a. amplitude b. stiffness c. harmonics d. thickness

b. stiffness

If the relative output power of an ultrasound system is calibrated in decibels and the operator increases the output by 10 dB, the beam intensity is increased: a. nine times b. ten times c. eight times. d. four times

b. ten times

The acoustic power of a sound wave is determined by: a. the near zone length b. the amplitude of the drive voltage c. the beam area d. the frequency of the drive voltage

b. the amplitude of the drive voltage

The period of a sound wave is determined by which of the following? a. the medium b. the sound source c. both the sound source and the medium d. none of the above

b. the sound source

Lateral resolution is directly dependent on:

beam width

What component of an ultrasound system determines the firing patterns of phasing?

beamformer

Lateral, azimuthal, or transverse resolution is determined by:

beamwidth

The effects of ultrasound on living tissue is called:

biological effects

A display that is limited to only black and white, with no other shades of gray is called

bistable

The doppler shift in frequency is directly proportional to

blood flow velocity

A vector phased array, real-time scanner produces a field of view shaped like a:

blunted sector

The image display created by the convex sequenced array is:

blunted sector

The wavelength of a sound wave is determined by:

both the source of sound and the medium

A B-mode signal is presented as a

bright spot

Irrespective of the frequency, the speed of sound in a medium is directly related to medium:

bulk modulus

A binary word is called a:

byte

If the power is decreased by a factor of two and all beam dimensions remain the same, the intensity is changed by: a. 3 dB b. -2 dB c. -3 dB d. -6 dB e. 6 dB

c. -3 dB

Normal incidence implies that the angle of incidence is equal to _______ degrees a. 180 b. 90 c. 0 d. 60

c. 0

What is the Half Intensity Depth of a transducer operating at a frequency of 8 MHz in soft tissue? a. 6.0 mm b. 1.54 mm c. 0.75 cm d. 2.0 cm

c. 0.75 cm

The color flow doppler packet is: a. the same as sample volume b. not adjustable in size c. an ensemble of pulses traveling together d. not related to temporal resolution

c. an ensemble of pulses traveling together

Which of these parameters best correlates with an increase in bulk modulus? a. decrease in the period b. decrease in material density c. increase in material stiffness d. increase in the transmit frequency

c. an increase in material stiffness

Which of the following transducer designs can change focus in both the lateral and elevation planes? a. all 1D phased arrays b. blind transducer c. annular array d. 1D phased sector e. linear sequential

c. annular array

Turbulent flow will result in an increase in spectral: a. duration b. direction c. broadening d. color velocity scale

c. broadening

Which mode allows only echoes from a specific depth to be displayed? a. a mode b. b mode c. c mode d. nyquist mode

c. c mode

A potential ultrasound bioeffect associated with high SPPA intensity is: a. impedance mismatch b. electrical shock c. cavitation d. miscarriage

c. cavitation

Which of the following will not result in a change in wavelength? a. change in period b. change in medium stiffness c. change in amplitude of the transmit signal d. change in medium density

c. change in amplitude of the transmit signal

The wavelength of ultrasound: a. changes with changes in the medium b. increases with decreasing propagation velocity c. changes with spatial pulse length d. none of the above

c. changes with spatial pulse length

The FFT is used to create the doppler spectral analysis for all of the following except: a. high PRF b. continuous wave c. color flow d. pulsed wave

c. color flow

Which of the following modes has the worst temporal resolution? a. B mode b. B scan c. colorflow d. M mode

c. color flow

When an acoustic wave travels through a medium, the tissue molecules change concentration. What is the highest level of concentration called? a. compactness b. excitation c. compression d. rarefaction

c. compression

Which of the following is defines as the angle at which there is total internal reflection? a. impedance angle b. angle of refraction c. critical angle d. angle of divergence

c. critical angle

The following are all components of the AIUM 100 mm test object except: a. stainless steel rods b. water c. cysts

c. cysts

What can cause banding on the image? a. oblique incidence b. low wall filter setting c . dead crystals d. refraction

c. dead crystals

Leaving all other parameters fixed but increasing the frequency will: a. decrease the period and increase the wavelength b. increase the period and decrease the wavelength c. decrease the period and decrease the wavelength d. decrease the period and leave the wavelength unchanged

c. decrease the period and decrease the wavelength

If the beam area is increased by a factor of 2 and the power is unchanged, the intensity will be: a. increased by a factor of 2 b. decreased by a factor of 4 c. decreased by a factor of 2 d. increased by a factor of 4

c. decreased by a factor of 2

For normal incidence, the percentage of transmission can be determined by the difference in: a. there is no transmission for normal incidence b. angle to interface and propagation velocities c. densities and propagation velocities d. the amount of refraction

c. densities and propagation velocities

Increasing the frequency improves all of the following except: a. axial resolution b. elevation resolution c. depth of penetration d. lateral resolution

c. depth of penetration

For the unfocused transducer, the best approximation of the beamwidth at a distance twice the near zone length from the transducer face is: a. cannot be determined b. 1/2 the aperature c. equal to the aperature d. twice the aperature

c. equal to the aperature

In phased array systems, dynamic beam focusing is achieved by which of the following? a. curving the crystals b. decreasing the transducer diameter c. firing patterns of time delays of the electrical pulses d. damping

c. firing patterns of time delays of the electrical pulses

Detail resolution will change with changes in any of the following except: a. focus b. increased frequency c. frame rate d. decreased SPL

c. frame rate

All of the following are related except: a. beam area b. amplitude c. frequency d. intensity e. power

c. frequency

Turbulent flow is most likely to occur in which one of the following situations? a. small diameter and high viscosity b. large diameter, low velocity c. high velocities and acute anemia d. large diameter, low velocity, low viscosity

c. high velocities and acute anemia

Low persistence: a. improves spatial resolution b. lowers frame rate c. improves temporal resolution d. reduces the dynamic range

c. improves temporal resolution

To achieve optimum resolution from a linear phased array, the beam is focused: a. mechanically b. in one plane only c. in two mutually perpendicular planes d. dynamically

c. in two mutually perpendicular planes

Which one of the following will increase the speed of ultrasound? a. decrease tissue stiffness b. decreased frequency c. increased tissue stiffness d. increased frequency

c. increased tissue stiffness

If a sound wave is traveling east to west the particles within the medium can be described as: a. up and down b. there is no particle motion c. left to right and right to left d.left to right only

c. left to right and right to left

For 2D imaging in soft tissue, the ultrasound system assumes that the Maximum imaging depth X ___________ = 77000 a. number of cycles x period b. frame time c. lines per frame x frame rate d. 13 usec/cm

c. lines per frame x frame rate

Ultrasound travels slowest through: a. soft tissue b. fat c. lung d. water

c. lung

A sound wave strikes a large smooth interface between two media orthogonally. The propagation speeds of the media are identical but their densities are different. Which of the following will occur? a. total transmission b. scattering c. reflection d. refraction

c. reflection

Rayleigh scattering of an ultrasound beam takes place when: a. there is an acoustic impedance mismatch b. the beam hits a smooth surface c. reflector size is much smaller than the ultrasound wavelength d. the beam is incident onto a rough or irregular surface

c. reflector size is much smaller than the ultrasound wavelength

The reduction in the amplitude and intensity of returning echoes due to highly attenuation structures: a. attenuation b. enhancement c. shadowing d. reverberation

c. shadowing

Which one of the following is not a propagation artifact? a. reverberation b. mirror image c. shadowing d. multipath

c. shadowing

Spatial resolution is associated with all of the following except? a. lateral resolution b. elevation resolution c. temporal resolution d. axial resolution

c. temporal resolution

Which of the following cannot be used to focus a beam in the far field? a. mirrors b. electronics c. the far field cannot be focused d. lens e. curved elements

c. the far field cannot be focused

Transducer A operates at 2 MHz. Transducer B operated with a 0.5 microsecond period. In a given patient which transducer will produce a sound wave of shorter wavelength? a. A b. B c. the wavelengths are the same d. cannot be determined

c. the wavelengths are the same

The fundamental frequency of a pulsed wave transducer is determined by: a. transducer type b. diameter of the crystal c. thickness of the crystal d. element propagation speed

c. thickness of the crystal

If particle displacement is perpendicular to the direction of wave propagation, the wave is called: a. longitudinal b. electromagnetic c. transverse d. torsion

c. transverse wave

Which one of the following is not true about Contrast Agents? They are a. small enough to pass through capillaries b. gas microbubbles entrapped in a shell c. unlikely to cause any side effects to the patient d. strong scatterers of ultrasound

c. unlikely to cause any side effects to the patient

The most likely artifact to result from a propagation velocity differing from the assumed 1540 m/sec is: a. comet tail b. longitudinal resolution c. speed error d. range ambiguity

c.speed error

The units that may be used to express doppler velocity is:

centimeters / second

The circumference of the aorta is measured in what unit?

cm

The units that may be used to express doppler velocity?

cm/sec

Color flow aliasing appears as:

color reversal

What causes the appearance of a color bleed through a vessel wall?

color wall filter set too low

A region of high pressure is called

compression

Leaving all other parameters fixed but increasing the frequency will __________ the period and ____________ the wavelength

decrease decrease

Which two parameters directly affect the natural focus of a transducer?

crystal diameter and operating frequency

The range of periods used for diagnostic ultrasound is: a. 0.05 sec - 0.05 msec b. depends on the medium c. 1 mm - 10 mm d. 0.5 microseconds - 0.08 microseconds

d. 0.5 microseconds - 0.08 microseconds

What is the frequency range for clinical ultrasound? a. 2-15 mHz b. 2-15 KHz c. 2-15 Hz d. 2-15 MHz

d. 2-15 MHz

A sound wave with an 8 MHz frequency travels 10 cm in soft tissue. What is the total attenuation that the sound beam experiences? a. 80 dB b. 8000 KHz c. 8 dB/cm d. 40 dB

d. 40 dB

Which ultrasound frequency is commonly used in the clinical setting? a. 5 kHz b. 3.5 kHz c. 10 kHz d. 7 MHz

d. 7 MHz

Which of the following frequencies will be associated with the longest wavelength? a. 100 kHz b. 2.5 MHz c. 15 MHz d. 8000 Hz

d. 8000 Hz

Which one of the following components of an ultrasound system converts echo voltage signals to bright spots? a. receiver b. transducer c. pulser d. CRT

d. CRT

Which of the following modes has time on one axis and depth on another? a. A mode b. B mode c. C mode d. M mode

d. M mode

When imaging depth is increased: a. PD is decreased b. SPL is increased c. Q-Factor is decreased d. PRF is decreased

d. PRF is decreased

Color flow doppler utilizes: a. varies b. CW c. High PRF d. PW

d. PW

Which of the following intensities has the highest value during pulsed ultrasound? a. SATA b.SPPA c. SPTA d. SPTP

d. SPTP

A digital scan converter: a. a part of a receiver b. part of a transducer c. performs FFT d. a computer memory

d. a computer memory

What is the definition of acoustic intensity? a. concentration of energy per unit time b. force per unit area of the sound beam c. work per unit area of sound beam d. acoustic power per unit area of the sound beam

d. acoustic power per unit area of the sound beam

Tissue doppler imaging: a. provides bidirectional information on the mean velocity of tissue motion b. is used with pulsed wave spectral doppler c. can be used with M-mode d. all of the above

d. all of the above

The spatial pulse length is equal to the number of cycles per pulse multiplied by the wavelength and does NOT depend on which of the following: a. period b. frequency c. propagation velocity d. amlitude

d. amplitude

Refraction is the amount a wave direction is altered at an interface and: a. rarely occurs in ultrasound because of the frequencies used b. changes with propagation velocity and density c. is determined by the acoustic impedance d. changes with propagation velocities and angle of incidence

d. changes with propagation velocities and angle of incidence

Which of the following reduces the dynamic range? a. TGC b. Demodulation c. Gain d. Compression

d. compression

Which of the following increases frame rate: a. increase field of view b. increase number of foci c. increase color packet size d. decrease image depth

d. decrease image depth

If the amplitude is decreased by a factor of 4 the power will be: a. decreased by a factor of 6 b. increased by a factor of 4 c. decreased by a factor of 8 d. decreased by a factor of 16

d. decreased by a factor of 16

The near field may be extended by increasing the transducer: a. thickness b. casing c. matching layer d. diameter

d. diameter

The compression control affects the: a. transducer bandwidth b. pulser voltage c. size of the field of view d. dynamic range of the receiver

d. dynamic range of the receiver

A region that is anechoic is displayed as: a. hyperechoic b. isoechoic c. echogenic d. echo-free

d. echo-free

Which of the following is true about laminar flow? a. flow that is noisy b. flow that has a tear drop shape c. flow that has the same width as the ultrasound beam d. flow with an organized velocity distribution

d. flow with an organized velocity distribution

In imaging, temporal resolution is determined by: a. overall gain b. pulse duration c. transmit gain d. frame rate

d. frame rate

Increasing the color packet size decreases: a. dwell time b. frequency c. pulse duration d. frame rate

d. frame rate

A potential ultrasound bioeffect maybe due to: a. low transmitter output and high receiver gain b. limited scanning time c. heat sterilizing transducers d. heating of tissues above 2 degrees Celsius

d. heating of tissues above 2 degrees Celsius

Temporal resolution is improved when: a. PRF is decreased b. SPL is increased c. beam width is increased d. imaging depth is decreased

d. imaging depth is decreased

Which one of the following is not an acoustic variable? a. density b. temperature c. acoustic pressure d. impedance

d. impedance

In the Fresnel Zone of the transducer, which of the following applies? a. intensity steadily fades with distance b. acoustic pressure is highest at the transducer face c. sound intensity remains uniform d. intensity fluctuations occur

d. intensity fluctuations occur

Which of the following transducers has a rectangular image? a. curved b. annular c. sector d. linear

d. linear

Sound is a: a. electromagnetic, transverse wave b. mechanical, transverse wave c. electromagnetic, longitudinal wave d. longitudinal, mechanical wave

d. longitudinal, mechanical wave

In order to limit patient exposure to acoustic energy, which method is best? a. high transmitter output and low receiver gain b. high reject and high transmitter output c. high near gain and low far gain d. low transmitter output and high receiver

d. low transmitter output and high receiver gain

If a transverse wave is traveling east to west the particles within the medium are displaced: a. west b. east and west c. depends on the medium d. north and south

d. north and south

Intensity is: a. attenuation b. pressure per unit area c. reflected portion d. power per unit area

d. power per unit area

If the propagation velocity in a medium is 3000 m/sec, the medium is: a. probably more dense than water b. probably stiffer than bone c. cannot be determined d. probably stiffer than soft tissue

d. probably stiffer than soft tissue

Another term for axial resolution is: a. transverse b. angular c. azimuthal d. radial

d. radial

The dynamic range of the receiver of an ultrasound system refers to the: a. ability of the receiver to track a moving structure b. depth range in tissue over which echoes can be received c. speed with which the receiver detects echo signal amplitudes d. range of echo amplitudes, from largest to smallest, that can be processed without distortion

d. range of echo amplitudes, from largest to smallest, that can be processed without distortion

In CW mode, if the drive frequency is 5 MHz and the crystal thickness is doubled, the transmit frequency will: a. quadruple b. halve c. double d. remain unchanged

d. remain unchanged

An increase in red blood cell velocity will result in an increase in the doppler: a. angle b. effect c. equation d. shift

d. shift

To improve spatial resolution in two-dimensional imaging, the Ultrasound system should be evaluated for: a. depth calibration accuracy b. attenuation c. doppler angle correction d. slice thickness

d. slice thickness

Which one of the following will NOT affect temporal resolution? a. packet size b. persistence c. maximum depth setting d. slice thickness

d. slice thickness

Which of the following is not an example of an electromagnetic wave? a. light b. x-ray c. heat d. sound

d. sound

The operating frequency of a dedicated CW doppler transducer is determined by: a. the thickness of the crystal b. the bandwidth of the ultrasound pulse c. the diameter of the crystal d. the frequency of the drive voltage

d. the frequency of the drive voltage

With color flow doppler, the colors represent: a. the viscosity of blood b. the volume of blood c. the maximum velocity of flow d. the mean velocity of flow

d. the mean velocity of flow

Aliasing is an artifact caused by the violation of: a. snell's law b. the doppler effect c. the Huygens principle d. the nyquist criterion

d. the nyquist criterion

The wavelength is: a. events per time b. the distance sound travels per second c. time to complete one cycle d. the physical distance one cycle occupies

d. the physical distance on cycle occupies

Snell's law states that: a. the depth of penetration decreases as frequency increases b. the angle of incidence is equal to the angle of refraction c. energy can neither be created nor destroyed d. the ratio of wave propagation speeds in two media in contact is proportional to the ratio of the sines of two angles

d. the ratio of wave propagation speeds in two media in contact is proportional to the ratio of the sines of two angles

Which of the following would likely be true given a boundary between two mediums, one with an acoustic impedance of 4 MRayls, and the second with an acoustic impedance of 4.1 MRayls? a. there would be a significant absorption b. there would be very little absorption c. there would be very little transmission d. there would be very little reflection

d. there would be very little reflection

An echo that has undergone an attenuation of 3 dB will have an intensity that is _______ than its initial intensity a. one time larger b. three times larger c. three times smaller d. two times smaller e. two times larger

d. two times smaller

Pulsed wave ultrasound is required for imaging because: a. narrow sound beam b. better resolution c. higher frequencies d. allows determination of reflector depth

d.allows for determination of reflector depth

In pulsed mode, doubling the crystal thickness will _________________ the frequency a. not change b. quadruple c. double d. halve

d.halve

A way to decrease spatial pulse length and pulse duration is:

damping

Contrast resolution is the ability to:

distinguish between echoes of slightly different intensities

The science of identifying and measuring characteristics of an ultrasound beam that are relevant to its potential for producing biological effects is called:

dosimetry

The ratio of the strongest echo amplitude to the weakest echo amplitude is called:

dynamic range

Which of the following is dependent on frequency? a. acoustic transit time b. stiffness c. impedance d. propagation velocity e. attenuation

e. attenuation

The ratio of the largest power to the smallest power that the ultrasound system can handle is the: a. amplification factor b. rejection range c. overall gain d. frequency factor e. dynamic range

e. dynamic range

Which of the following relates to bandwidth and operating frequency? a. piezoelectric crystal b. matching layer c. near zone d. far zone e. quality factor

e. quality factor

Which of the following is the least likely cause for attenuation? a. bone b. absorption c. reflection d. scattering e. refraction

e. refraction

What is the name of the mechanism of ultrasound bioeffects in which microbubbles oscillate without collapsing? a. fluid streaming b. ionizing c. transient d. thermal effect e. stable

e. stable

The principle difference between electromagnetic waves and mechanical waves is:

electromagnetic waves can work in a vacuum

Matrix array transducers decrease slice thickness which improves:

elevation resolution

All waves transfer _____ through cyclical variations

energy

The increase in amplitude and intensity of returning echoes due to low attenuation structures:

enhancement

The propagation speed in medium 1 is 1510 m/s. The propagation speed in medium 2 is 1630 m/s. The angle of incidence is 33 degrees. What is the angle of reflection?

equal to 33 degrees

Mechanical transducers have __________ focus

fixed

Lateral resolution is best in the:

focal point

The far field of an ultrasound beam may be called:

fraunhoffer

Period is the reciprocal of:

frequency

The attenuation coefficient is dependent on:

frequency

The attenuation coefficient will increase if there is an increase in:

frequency

The near zone length of a transducer depends on

frequency and transducer diameter

The formula for Quality Factor is:

frequency divided by bandwidth

A unit of density used in the metric system is:

g/cm³

The color Doppler wall filter will reduce the artifact called:

ghosting

The color doppler artifact where color flow is placed on moving structures:

ghosting

The propagation speed in medium1 is 1510 m/s. The propagation speed in the medium 2 is 1630 m/s. The angle of incidence is 33 degrees. What is the angle of transmission? (>, =, < 33 degrees?)

greater than 33 degrees

If the thickness of the crystal doubles, the operating frequency for PW mode:

halves

The transmission of a fundamental frequency and the reception and processing of a second higher frequency is called:

harmonic imaging

The number of cycles per second is a:

hertz

Wall motion frequency shifts are _______ amplitude ______ velocity

high amplitude low velocity

Increasing the color doppler line density will _____Color doppler resolution but will _______ the frame rate

improve decrease

If frequency increases, resolution?

improves

An increase in transmit gain will ______the electrical voltage from the pulser to transducer:

increase

The image depth is decreased by the sonographer. The pulse repetition frequency will:

increase

The pulse repetition period will ________ with increasing image depth?

increase

If the vessel lumen doubles while pressure gradient is maintained constant, then the flow rate will:

increase 16 times

As frequency increases, total attenuation:

increases

As image depth increases, total attenuation:

increases

As the number of cycles in a pulse decreases, the spatial pulse length decreases, and the bandwidth ________ and axial resolution _______

increases improves

If the frequency doubles, the NZL:

increases by a factor of 2

An increase in the strength of the ultrasound pulse will increase:

intensity

The major advantage of continuous wave doppler:

lack of aliasing

Which resolution has the ability to resolve closely spaced structures which lie perpendicular to the sound beam?

lateral

Matching layers in transducer construction are used to _________ while a backing material is used to __________.

lessen impedance mismatch dampen the SPL

If particle displacement is parallel to the direction of wave propagation, the wave is called:

longitudinal wave

During color Doppler, deeper, more saturated color represents:

low velocity flow

What units are used to measure intensity in an ultrasound application?

mW/cm2

What does the following definition describe " used to minimize the acoustic impedance mismatch between the crystal and the tissue"

matching layer

Color Doppler provides __________ velocities

mean

Color doppler provides ____________ velocities

mean

Pulse duration is measured in: a. unitless b. Hz c. microseconds d. m/s

microseconds

What is the unit associated with measuring the circumference of a circle?

mm

In a Doppler spectrum, the most commonly encountered velocity is called:

modal velocity

Turbulent flow on color Doppler is shown as:

mosaic

The formula for SPL is:

n x wavelength

The Fresnel zone is:

near field

Red blood cells moving away from the transducer will result in a doppler shift that is:

negative

What unit is used to express duty factor?

none

When a sound beam is perpendicular to the reflector it is called:

normal

Compensation is used for

normalizing gain differences due to attenuation

Any incidence that is not perpendicular incidence is called:

oblique

The flow profile characterized by slightly higher velocities in the center of a vessel and lower velocities closer to the vessel wall, is called:

parabolic flow

Pulse duration is expressed in the same units as the: a. period b. wavelength c. speed of sound d. density

period

The pulse duration is the time for a pulse to occur and equals the:

period x n (number of cycles in a pulse)

What averages signals to reduce noise but results in poor temporal resolution

persistance

The material that has the ability to convert acoustic pressure to electrical energy

piezoelectric

The smallest picture element in a digital image is the

pixel

The unit used to measure the viscosity of blood is:

poise

When constructing ultrasound transducers, multiple matching layers are used to

reduce acoustic impedance mismatch

Sound energy returned to the source is called?

reflection

As a sound wave crosses boundary it may bend. This is called:

refraction

Snell's law describes:

refraction

The artifact associated with a change in the direction of the beam as it crosses an interface:

refraction

Edge shadowing occurs when the US beam:

refracts and diverges

The process of eliminating weak, low amplitude echo signals from further processing is called:

reject

What receiver function eliminates weak signals?

rejection

The reasons why diagnostic ultrasound frequency rages from 2 MHz to 17 MHz is that the low end is restricted by ____________ and the high end is restricted by _________.

resolution, penetration

Venous pressure and flow are affected by:

respiration

A potential artifact due to the presence of 2 strong reflectors in the path of a beam is:

reverberation

The artifact associated with multiple reflections equally spaced:

reverberation

Spectral analysis is the process of:

separating a signal into its frequency components for quantification

A change in the frequency of sound relative to the motion of the source and/or the observer is known as the Doppler

shift

An increase in the Doppler transmit frequency will result in an increase in the Doppler:

shift

The highest Doppler shift that can be measured without the appearance of aliasing is:

the nyquist limit

What determines the initial intensity of the ultrasound beam?

the source

The operating frequency of a pulsed ultrasound transducer is determined by the:

thickness of the crystal

The ultrasound control which specifically compensates for attenuation is ________ gain

time

If the speed of sound in the medium is greater than 1540 m/sec, the echo will be placed:

too close to the transducer

The pulser delivers an electrical voltage to the :

transducer

Which component of an ultrasound system can potentially present an electrical hazard to the patient?

transducer

According to the Reynold's equation, if viscosity increases

turbulence decreases

Increased spectral broadening and window fill-in represents blood flow that is assumed to be:

turbulent

The unit for duty factor:

unitless

Which control eliminates doppler shift information due to wall and/or blood vessel motion:

wall filter

Specular reflections occur:

when the interface is larger than the wavelength

In what area of a stenotic blood vessel does the maximum velocity of blood occur?

within the stenosis

The Doppler shift is 5,000 Hz. The PRF is 9,000 Hz. Will aliasing occur?

yes