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