| Terms |
Definitions |
|
billionth
|
nano
|
|
Pressure
Density
Distance
|
Three acoustic variables
|
|
Near zone
|
Fresnel zone
|
|
Ultrasound transducers operate according to the principle of what?
|
Piezoelectricity
|
|
Device that accomplishes amplification
|
Amplifier
|
|
B-MODE STANDS FOR?
|
BRIGHTNESS MODE
|
|
21. Period is inversely proportional to:
|
a. velocityb. wattsc. hertzd. frequency
|
|
Propagation speed is higher through:
a. lung
b. blood
c. liver
d. bone
|
D
|
|
Pressure,density and particle vibration; sound wave quantities that vary in space and time
|
Acoustic Variables
|
|
RAYLEIGH SCATTERING IS RELATED TO_________.
|
FREQUENCY
|
|
directly
|
Time-of-flight and depth are ______ related.
|
|
sound source
|
Intensity is determined by what?
|
|
30. The following are acoustic variables, except
|
a. temperatureb. densityc. particle motiond. particle speed
|
|
Is the following operator adjustable: compensation and rejection?
|
Yes
|
|
Define Q factor.
|
Recriprical of fractional bandwidth
|
|
Absorption:
|
sound energy converted into heat energy
|
|
16. If the intensity has been quartered, than the amplitude has been,
|
a. halved
b. doubled
c. quadrupled
d. unchanged
|
|
While preforming an abdominal ultrasound examination, you encounter the following interfaces. Which will produce the strongest reflected signal? Spleen/kidney, Liver/pancreas, Liver/Bowel gas, Liver/bile duct, Renal cortex/ renal sinus
|
Liver/bowel gas
|
|
What is the unit of impedance?
|
Rayl
|
|
Which component adjusts the amplitude of the received echoes:
|
output
|
|
What system somponent determines the pulse repitition frequency?
|
Pulsar
|
|
Density multiplied by the sound propagation speed
|
Impedance
|
|
A diplay presentation of echo amplitude versus depth
|
A-mode
|
|
Ultrasound instrument that combines gray-scale sonography with pulsed doppler and possibly, continuous wave doppler
|
Duplex instrument
|
|
Small transducer element mounted on the end of a narrow tube; a piesoelectric membrane with small metallic electrode
|
Hydrophone
|
|
THE DIFFERENCE BETWEEN THE AVERAGE VALUE AND THE MAXIMUM VALUE OF AN ACOUSTIC VARIABLE.
|
AMPLITUDE
|
|
"PORN 90"PerpendicularOrthagonalRight angleNormal90˚
|
Other names for normal incidence
|
|
Related
|
Two itemss that are associated or affiliated
|
|
none
|
What are the units for quality factor?
|
|
You have placed the Doppler sample volume in a vessel that is 3cm deep. How long will it take the reflected signal to arrive back at the transducer?
|
39microseconds
|
|
What are the frequencies of audbile sound?
|
20Hz-20,000Hz
|
|
28. The term which denotes the encounters of a pulse with scatterers at any point in its travels is
|
a. specular reflections
b. backscatters
c. speckle
d. contrast
|
|
Transducer
|
anything which converts one form of energy to another form of energy. Ultrasound transducers use the piezoelectric effect to convert electroptential energy to mechanical energy and vice versa
|
|
Increasing the frequency on a multifrequency transducer from 3.5 to 5.0 MHz will do what to what wavelength?
|
Decrease it
|
|
If the density of the medium increases, the speed of sound will:
a. increase
b. decrease
c. not change
|
D
|
|
Normally, the number of channels utilized does not exceed the number of:
|
transducer elements
|
|
What term describes the ability of sound to separate closely spaced objects?
|
Resolution
|
|
When the velocity of blood flow exceeds the doppler nyquist limit, what occurs?
|
Aliasing
|
|
The attenuation coeffient is expressed in:
a. mW/cm^2
b. dB/cm
c. dB
d. MHz/cm
|
b. dB/cm
|
|
What function of the receiver converts electrical signals from radiofrequency to video form?
|
Demodulation
|
|
You have decreased the scan line density during a color doppler exam of the Kidney, what technique will be employed to fill in the empty data between the scan lines?
|
Interpolation
|
|
Change of sound direction on passing from one medium to another
|
Refraction
|
|
A back-lighted rectangle matrix of thousands of liquid crystal display elements
|
Flat-panal diaplay
|
|
improper doppler shift info from a pulsed wave doppler or color doppler when the true doppler shift exceeds one half the PRF
|
Aliasing
|
|
Ratio of amplifier output to input electric power
|
Gain
|
|
Transmitted intensity divided by incident intensity; the fraction of incident intensity transmitted into the second medium
|
Intensity tranmitted coeffcient
|
|
WHAT DOES "PZT" STAND FOR?
|
LEAD ZIRCONATE TITANATE
|
|
distance of reflector(mm) = 1.54mm/µs x go-return time(µs) / 2
|
equation for depth
|
|
acoustic propagation
properties
|
The effects of the medium upon the
sound wave
|
|
17. Which of the following has the slowest propagation speed
|
a. lungb. soft tissuec. fatd. bone
|
|
What is the Doppler effect presented when the source and the receiver are moving closer together or further apart?
|
Frequency shift
|
|
What happens to duty factor when Imaging depth increases?
|
DF decreases
|
|
What best describes an angle with a measurement of 133degrees?
|
Obtuse
|
|
The dependance on Doppler angle is in the form of a waht?
|
Cosine
|
|
What is the distance from the transducer to the center of the focal region?
|
Focal Length
|
|
Propagate
|
- a means of transmission from one location to another location through interaction. Sound propagates through a medium by interacting with particles within the medium.
|
|
You are imaging a structure that is highly attenuating, WHat effect would you expect to encounter?
|
Shadowing
|
|
The rate at which work is done referred to as:
a. pressure
b. intensity
c. power
d. amplitude
|
C
|
|
The amount of space within a specific boundary defines:
|
area
|
|
What means attenuation?
|
Decrease in intensity and amplitude when the sound travel through a medium
|
|
Which of the following transducers produces side lobes: Mechanical sector, Linear sequential array, Phased array, Convex array or all
|
All of them
|
|
What are the units of measure for doppler shift?
|
KHz
|
|
What are the units for duty factor?
a. Hertz
b. Mm/microseconds
c. dB
d. None (unitless)
|
d. unitless
|
|
The technique of frame averaging during real time acquisition is designed to do what?
|
Reduce random noise
|
|
Primary frequency in a collection of frequencies that can include odd and even harmonics and subharmonics
|
Fundamental frequency
|
|
Digital computer implementaion of the fourier transform
|
Fast Fourier Transform
|
|
THE PERCENTAGE OR FRACTION OF TIME THAT THE SYSTEM TRANSMITS SOUND:
|
DUTY FACTOR
|
|
AS WELL AS POWER, INTENSITY IS PROPORTIONAL TO__________.
|
AMPLITUDE SQUARED.
|
|
WHAT DOES SAPA STAND FOR?
|
SPATIAL AVERAGE, PULSE AVERAGE.
|
|
0.004 - 0.090 watts
|
In clinical imaging, typical powers range from what?
|
|
What are the general frequencies used in ultrasound imaging and name a type of exam used for the transducers.
|
2.0-Cardiac, 3.5-OB/Abdominal, 5.0-Vascular, 7.5-Superficial, 10.0-Small parts
|
|
What happens to duty factor when PRP increases?
|
DF decreases
|
|
27. Scattering refers to:
|
a. bending of the sound beam crossing a boundary
b. conversion of sound to heat
c. redirection of a portion of the sound from a boundary beam
d. redirection of the sound beam in several directions
|
|
An interation of echoes that leads to reinforcement rather than to partial or total cancellation is known as what?
|
Constructive interference
|
|
A sudden burst of color Doppler most likely represents:
|
flash artifact
|
|
You are performing an ultrasound exam with a wide bandwith transducer. What is the advantage you obtain with this transducer compared to a narrow bandwith transducer?
|
Improved Axial resolution
|
|
If you wish to adjust the focusing characteristics while scanning with a curved linear array, what type of focusing are you manipulating?
|
Multizone transmit
|
|
The PRF is realated to depth of pulse travel.
True or False
|
True
|
|
Which mode makes the best use of contrast resolution?
a. A-mode
b. B-mode
c. M-mode
d. None of the above
|
b. B-mode
|
|
The ratio of the largest to the smallest signal that a system can handle is termed what?
|
Dynamic range
|
|
Thickness of the scanned tissue volume perpindicular to the scan plane
|
SLice thickness
Section thickness
|
|
THE PROP SPEED FOR PZT IS APROX:
|
4-6mm PER SECOND
|
|
NAME 3 CHARECTERISTICS OF BACKING MATERIAL:
|
-DECREASED OUTPUT POWER
-DECREASED TRANSDUCER SENSITIVITY
-DECREASED "Q" FACTOR
|
|
boundaries that have irregularities approximately the same size as the wavelengthno
|
When does diffuse reflection occur?Is it organized?
|
|
0.05 - 0.5 mm
|
What are typical values of LARRD resolution?
|
|
What parameters can a hydrophone measure?
|
Amplitude and period; Acoustic pressure output levels, intensities and output indexes
|
|
6. PRF is the # of pulses occurring per
|
a. time
b. second
c. pulse
d. none of the above
|
|
If you choose a lower freq transducer to image a highly attenuating liver, what tradeoff are you making?
|
Decreased Spatial resolution
|
|
Which of the following may directly affect the intensity of the Doppler signal:
A. pressure gradient
B. radius of the vessel
C. length of the vessel
D. velocity of the RBC
E. concentration of RBC
|
E. concentration of RBC
|
|
You have detected a small hyperechoic focus within the gallbladder. There is no distal acoustic shadow. What can you do to aid visualization of the shadow?
|
Increase the transducer frequency
|
|
The round trip pulse travel time and distance to the reflector can be determined by using the:
a. Bernoulli equation
b. Range equation
c. Snell's Law
d. None of the above
|
b. Range equation
|
|
Gel used to provide a good sound path bewteen a transducer and the skinby elininating the air between the 2
|
Coupling medium
|
|
THE X-AXIS ON B-MODE IS:
|
REFECTOR DEPTH MEASURED BY PULSE'S TIME-OF-FLIGHT
|
|
Ultrasound system and transducer
|
What is the source of a sound wave?
|
|
7. Which of the following has a higher acoustic impedance coefficient
|
a. gasb. solid c. liquidd. all of the above have an equal acoustic impedance coefficient
|
|
Define: propagation speed artifact.
|
Occurs when the assumed prop speed is incorrect
|
|
20 dB means_____
|
ten times, ten times. The final is 100 times bigger than the original intensity.
|
|
You have increased the transmit power while performing a pelvic ultrasound. Which actions does this increase?
|
Penetration, Acoustic power, Image brightness, and the voltage applied to the crystals
|
|
Which of the following best describes spatial compounding:
A. smoothes non-specular surfaces
B. interrogates the structures once
C. continuous wave transducers utilize spatial compounding
D. Speckle is increased when utilizing
E. improves visualization be
|
E. Spatial compounding improves visualization beneath highly attenuating structures.
|
|
What positive result will occur from the action taken when You increased the packet size while using color doppler to evaluate flow in the thyroid gland
|
Improved signal to noise ratio
|
|
Two separate fields are used to produce an image on a video monitor. The purpose of this is to do what?
|
Reduce flicker in the monitor
|
|
WHAT IS THE MEANING, PREFIX, AND SYMCOL FOR THE FOLLOWING:
1.10^9
2. 10^6
3. 10^3
4. 10^-3
|
1. BILLION-GIGGA- G
2. MILLION-MEGA- M
3. THOUSAND-KILO-k
4. THOUSANDTH-MILLI-m
|
|
10dB = 10x bigger20dB = 100x bigger (10 x 10)
|
10dB rule for positive numbers
|
|
Two Part QuestionWhat type of image does convex array produce? What is the complete name of convex array?
|
1. Sector Type2. Convex sequenced array
|
|
What is a scan converter?
|
A device used to reformat echo data into image form for image processing, storage, and display (image memory)
|
|
Subdicing the grating
lobe artifact....
|
Grating lobe artifact can be reduced or cured by dividing each element into even smaller miniature pieces this is called subdicing.
|
|
The width of the element in a linear phased array transducer is approximately:
|
one-quarter of the wavelength
|
|
Which statement is not true regarding color doppler imaging: color doppler requires a min of 3 pulses per scan line, color doppler can alias and has limitations, color doppler is a quantitative technique, or color doppler utilizes PW doppler?
|
Color doppler is a quantitative technique
|
|
Which display mode may be used to calculate distance measurement?
|
A, B, and M modes
|
|
WHAT ARE THE PROPAGATION SPEEDS OF THE FOLLOWING?:
AIR, BLOOD (SOFT TISSUE), TENDON
|
AIR- 330 m/s
BLOOD (ST)- 1540m/s
TENDON- 1850m/s
|
|
What are the 3 modes of focusing for a mechanical transducer?
|
Lens, Curved element, Mirrors
|
|
What is the relationship of frequency to absorption?
|
If frequency is doubled, absorption is doubled
|
|
Window filling of the spectral tracing is due to what?
|
Turbulent flow, Sample gate too large, SV placed too close to the vessel wall, Gain to high
|
|
The incoming raw echo signals must be compressed into smaller dynamic range because: A wide dynamic range results in increased display of electronic noise, A wide dynamic range does not allow differentiation between echoes arriving from different depths,
|
The display cannot accommodate the wide dynamic range of the incoming signals
|
|
axial resolution(mm) = 0.77 x # of cycles in pulse / frequency(MHz)
|
equation for axial resolution in soft tissue
|
|
What region lies beyond a distance of one near-zone length? Name all three names?
|
1. Far zone
2. Far field
3. Fraunhofer zone
|
|
The transducer you are using to image the liver transmits a wide beam of 3-5MHz. Describe the beam after it has transversed the liver?
|
The reflected bandwith will be shifted down in frequency due to the increased attenuation of higher frequencies
|
|
What does the term duty factor describe?
|
The fraction of time the transducer is actively transmitting sound
|
|
THE CENTER FREQUENCY IN PULSED TXRS IS DETERMINED BY 2 CHARECTERISTICS OF THE CRYSTAL:
|
-THE THICKNESS
-THE PROP. SPEED OF THE PIEZOELECTRIC MATERIAL
|
|
The spatial resolution of the scan converter is determind how?
|
By the number of pixels in the scan converter matrix
|
|
millionth
|
micro
|
|
x-axis
|
The horizontal axis
|
|
NARROW BEAMS=??
|
BETTER IMAGES
|
|
What does in-vivo dentoe?
|
Within
|
|
Curved linear array
|
Convex array
|
|
M-MODE STANDS FOR:
|
MOTION MODE
|
|
To improve resolution, diagnostic tranducers are what?
|
Focused
|
|
WIth perpendicular incidence, the larger the impedance difference between the media, the greater the:
|
reflection
|
|
As low as reasonably achievable
|
ALARA
|
|
-DECREASED OUTPUT POWER
-DECREASED TRANSDUCER SENSITIVITY
-DECREASED "Q" FACTOR
|
BACKING MATERIAL
|
|
reflectionscatteringabsorption
|
3 processes that contribute to attenuation
|
|
Interference
|
These waves lose theri individual characteristics at that moment and combine to form a single wave
|
|
What elements convert electric voltage into ultrasound pulses and convert returning echoes back into voltages?
|
Piezoelectric Elements
|
|
Is the following operator adjustable: amplification and compensation?
|
yes
|
|
What is the formula for wavelength?
|
wavelenght=c/f
|
|
Stiffness and speed = ______ directions
|
same
|
|
11. In oblique incidence, if the propagation speed of the 2 medium are equal, their will be no reflection
|
a. true
b. false
|
|
What interaction is associated with divergence of the sound beam after passing through a small aperature?
|
Diffraction
|
|
Which of the folloqing intensities would be the greatest for a pulsed beam of sound?
a. SATA
b. SPTA
c. SPTP
d. SATP
|
C
|
|
Turbulent blood flow will likely demonstrate:
|
eddies
|
|
Are the following pre or post-processing procedures: Write Zoom?
|
Pre
|
|
Decrease in amplitude and intensity with distance as a wave travels through a medium
|
Attenuation
|
|
Reflected frequency minus incident frequency; a change in frequency that occurs as a result of motion
|
Doppler shift
|
|
WHAT ARE THE UNITS OF POWER?
|
WATTS
|
|
ANOTHER PHRASE FOR "NORMAL INCIDENCE" AND "ORTHOGONAL" IS :
|
RIGHT ANGLE
|
|
16 times greater
|
When frequency doubles, Rayleigh scattering is _____ times _______.
|
|
Amplitude
Power
Intensity
|
Three parameters describe the size, or magnitude, or strength of a sound wave
|
|
width of sound beam
|
What determines LATA resolution?
|
|
Define bandwith.
|
The range of frequencies contained within a pulse
|
|
The decrease in intensity, power and amplitude as the sound wave travels is termed:
|
attenuation
|
|
2. If frequency in soft tissues is doubled, propagation speed is
|
a. halved
b. doubled
c. decreased
d. unchanged
|
|
Axial resolution
|
-the ability to distinguish between two structures in the axial (longitudinal, radial, depth or range) dimension. The axial resolution equals the spatial pulse length (SPL) divided by 2
|
|
In sound wave propagation, the region of elevated pressure is termed what?
|
Compression
|
|
Which statement is most correct about power?
a. rate of work
b. is expressed as mW/cm 2
c. power and intensity are always the same
d. power is = to the transfer of energy
|
A
|
|
Which of the following demonstrates the fastest propagation speed:
A. air
B. fat
C. blood
D. muscle
E. soft tissue
|
D. muscle
|
|
Which represents the best measure of resolution for modern day ultrasound scanner: Contrast, Axial, Elevation, Temporal, or Lateral?
|
Axial
|
|
The orapid technique used in most color doppler systems to obtain the mean soppler frequency shift is known as what?
|
Autocorrelation
|
|
The compensation controls which determines the depth where amplification of signals begins:
a. near gain
b. far gain
c. TGC slope
d. reject
|
c. TGC slope
|
|
You have adjusted several system controls and notice that the frame rate has decreased to a level that makes scanning difficult. What is a typical fram rate for B-Mode real-time imaging?
|
10-50 Hz
|
|
The ability to distinguish between adjacent structures producing echoes of similar amplitude is termed what?
|
Contrast Resolution
|
|
Ability to distinguish closely spaced events in time
|
Temporal resolution
|
|
Diffusion or redirection of sound in several directions upon encountering a particle suspension or a rough surface
|
Scattering
|
|
Detail resolution in the direction perpindicular to the scan plane. It is equal to the section thickness and the source section thickness artifact
|
Elevational resolution
|
|
Process by which small voltages are increased to larger ones
|
Amplification
|
|
Curved material that focuses a sound or light beam
|
Lens
|
|
LIST THE 7 PARAMETERS THAT DESCRIBE SOUND WAVES:
|
1.PERIOD
2.FREQUENCY
3.AMPLITUDE
4.POWER
5.INTENSITY
6.SPEED
7.WAVELENGTH
|
|
PRP(µs) = imaging depth(cm) x 13µs/cm
|
equation for PRP
|
|
transducer diameterfrequency of sound wave
|
What determines focal length?
|
|
29. If the wavelength is 8mm, the SPL for a 2 cycle pulse is,
|
a. 4mmb. 6mmc. 8mmd. 16mme. 24mm
|
|
In standard Doppler, what is known about the reflected frequency produced by RBCs traveling in a direction away from the transducer: It is in the audible range, It is ultrasonic, Its greater than the transmitted frequency, or its less than the transmitted
|
Its ultrasonic
|
|
How are spatial pulse length and pulse duration related?
|
Directly
|
|
Define: harmonics.
|
Frequencies that are even or odd multiples of another commonly fundamental/operating frequency; 2nd operating frequency
|
|
What converts one form of energy to another?
|
Transducers
|
|
Acute angle
|
an angle between 0 and 90 degrees
|
|
When your patient asks you how much longer the exam will take, his voice is in the audible frequency range. What is an audible frequency range?
|
10kHz
|
|
What must occur for blood to flow:
|
pressure gradiant
|
|
The onset of turbulence is determined by the:
|
Reynolds number
|
|
Which are the process that affect attenuation
|
apsortions
reflection
scattering
beam divergence
|
|
The ultrasound system in your lab has multiple transducers that exhibit different axial resolution for the following axial resolution measurement, which offers the finest detail: .77, .44, .31, .20, or .15mm
|
.15mm
|
|
Color flow imaging utilizes what type of Doppler?
|
PW doppler
|
|
The turning of negative voltages into positive ones is a process called:
a. smoothing
b. rectification
c. enhancement
d. compression
|
b. rectification
|
|
Mirror image artifacts occur because of: (more than one answer may apply)
a. too much doppler gain
b. Nyquest limit exceeded
c. poor doppler angle
d. wall filter too low
|
a and c
|
|
When you adjust the output power, you affect the following system component: Pulsar, Beam former, Scan converter, memory, or receiver?
|
Pulsar
|
|
COnstant display of one of the frames in memory
|
Freeze-frame
|
|
Ability of a gray-scale display to distinguish bewteen echos of slightly different intensities
|
Contrast resolution
|
|
RETURING ECHOES ARE PRESENTED AS SPOTS ON THE LINE OF TRAVEL OF THE EMITTED US PULSE.
|
B-MODE SCANNING
|
|
A PROPERTY OF CERTAIN MATERIALS TO CREATE A VOLTAGE WHEN THEY ARE MECHANICALLY DEFORMED.
|
PIEZOELECTRIC EFFECT
|
|
Bioeffects
|
The effects of the sound wae upon the biologic tissue through which it passes
|
|
What is the main pulse that is emitted from the transducer termed?
|
Operating/Resonance
|
|
If frequencyy is doubled what hapens to the wavelength?
|
It is halved
|
|
What can be said of the Doppler shift when the sound beam is normally incident to the velocity of the red blood cells?
|
?
|
|
18. Which of the following is the most dominant factor that contribute to attenuation
|
a. propagation speed
b. reflection
c. absorption
d. scattering
|
|
WHat is the velocity of an ultrasound wave in bone?
|
4080 m/s
|
|
Which of the following resolutions inversely relates to the number of focal zone frame:
A. axial
B. spatial
C. lateral
D. contrast
E. temporal
|
E. temporal
(temporal resolution inversely relates to the number of focal zones, number of lines per frame and penetration depth utilized)
|
|
What is the location where the sound beam reaches its narrowest diameter known as?
|
Focal Zone
|
|
No flow in a vessel would be indicated by what color?
|
Black
|
|
the phenamenon that occures when the beam strikes a small reflector with a diameter of less than the sound wavelength is referred to as:
a. specular reflections
b. Rayleigh's scattering
c. snell's scattering
d. none of the above
|
b. Rayleigh's scattering
|
|
The attenuation coefficient for soft tissue is equal to______ db/cm per MHz of frequency.
a. 3-5
b. 5-1.1
c. 1.1-2.0
d. 0.5-1.0
|
d. 0.5 - 1.0
|
|
While performing an OB US exam, you decide to adjust the system parametes to improve the image. WHich of the following is not adjustable by operator control on the US system: fREQ, Power, Intensity, AMplitude, and Prop speed.
|
Prop speed
|
|
Speed with which a wave moves through a medium
|
Propagation speed
|
|
THE RATE THAT SOUND TRAVELS THROUGH A MEDIUM IS KNOWN AS:
|
PROPAGATION SPEED
|
|
THESE ARE KNOWN AS " THE EFFECTS OF THE SOUND WAVE UPON THE BIOLOGIC TISSUE"
|
BIOLOGIC EFFECTS
|
|
1)air2)bone3)lung4)soft tissue5)water
|
Arrange in order from most to least attenuation:soft tissue, air, lung, water, bone
|
|
internal focusing
|
This type of focusing is a result of using a curved active element.
|
|
What are the effects of medium upon the ultrasound wave called?
|
Acoustic propagation properties
|
|
8. According to the range equation, which of the following are necessary to calculate the distance
|
a. attenuation coefficient & type of reflector
b. density & type of reflector
c. propagation speed & pulse roundtrip travel time
d. density & pulse roundtrip travel time
|
|
You are scanning a patient with suspected gallstones using a 3.5MHz transducer. You do not ditect shadowing distal to the suspected gallstone. What can you do to enhance the visibility of the acoustic shadow distal to a gallstone?
|
Increase the transducer frequency
|
|
Thermal index has a low risk of adverse effects if the value is:
|
less than 2
|
|
You are using a type of focusing that varies the number of cycles being fired in a segment, what is this called?
|
Aperature focusing
|
|
What is the minimum frame rate to avoid image flickering during real time?
a. 5 fps
b. 10 fps
c. 15 fps
d. 20 fps
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c. 15 fps
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The largest range of output intensities is seen with:
a. imaging
b. pulsed doppler
c. color doppler imaging
d. conbination of all three
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d. combination of all three
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Region of a sound beam in which the beam diameter decreased as the distance from the transducer increases
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Near zone
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SOUND BEAM DIVERGENCE IS DETERMINED BY 2 FACTORS:
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-TRANSDUCER DIAMETER
-FREQUENCY OF US
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1540m/s or 1.54 mm/µs
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What is the speed of sound in soft tissue?
|
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8. According to the range equation, which of the following are necessary to calculate the distance
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a. attenuation coefficient & type of reflectorb. density & type of reflectorc. propagation speed & pulse roundtrip travel timed. density & pulse roundtrip travel time
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What type of intensity does heating depend on?
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SPTP- Spatial peak Temporal peak
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What is the preferred or natural frequency for an element? Two names?
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1. Operating Frequency
2. Resonance Frequency
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For pulsed ultrasound, the following factors determine the frequency of the sound wave: Pulse repitition frequency, propagation speed of the piezoelectric material, thickness of the piezoelectric material, B & C, or A & B & C
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B propagation speed of the piezoelectric material & C Thickness of the piezoelectric material
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The area from the transducer to the spatial peak intensity is termed:
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near field
(spatial peak intensity=focus)
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The doppler shift frequency from moving reflectors is what?
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The difference between the transmitted and received ultrasonic frequencies
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Color frame rate is effected by all of the following except:
a. sector size
b. color box size
c. color gain
d. PRF
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c. color gain
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Which of the following is the most reaspnable action to take if the image on the US system displays only echoes arising from bright reflectors at all depths? However no weak reflectors appear anywhere on the image: Adjust the systems compensation, Increas
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Adjust the reject level
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2-D IMAGES MAY BE REFERED TO AS _____ OR _____ SINCE THEY ARE GRAY SCALE.
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B-SCANNS OR B-MODES
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boundaries that are similar to or smaller than the wavelengthnolung
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When does scatter occur?Is it organized?Example of scatterer?
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What is a beam profiler?
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A device used to record 3D reflection and amplitude information
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In soft tissue, attenuation coefficient (dB/cm) is estimated at approximately:
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half of the freq (Mhz), or 0.5 dB/cm/Mhz
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If the number of cycles in a pulse is increased but the wavelength remains the same, what happens to the pulse duration?
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It is increased
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Intensity in a sound beam is highest:
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near the center of the beam
|
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The color image and spectrum analysis provided are indicative of a high grade stenosis because of what?
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Elevated peak velocity and post stenotic turbulence
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What receiver function listed is not operator adjustable: Amplification, Compression, Demodulation, Rejection?
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Demodulation and Compression are not receiver operator adjustable
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reflector is much smaller than the wavelengthyesred blood cell
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When does Rayleigh scatter occur?Is it organized?Example of a Rayleigh scatterer?
|
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What is the source of the enhancement artifact?
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Decreased attenuation through a weakly attenuating structure
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In order to image deeper structures the US system must:
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decrease the number of pulses per second
|
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All of the following are true regarding color doppler except: Color doppler will not alias, color doppler is qualitative data, color doppler is a pulse doppler technique, or color doppler uses autocorrelation processing?
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Color doppler will not alias is flase
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What is the advantage of using Write Zoom instead of Read Zoom magnification?
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Write Zoom provides better spatial resolution than Read Zoom
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PZT is 4mm.Matching layer is 2mm.
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If a wavelength is 8mm, how thick is the transducer's PZT? How thick is its matching layer?
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What is the assumption # for cross talk?
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Assumption # 2 Sound travels directly to the reflector and back to the transducer.
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What is the period of a 10.0 MHz cycle:
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0.10 microseconds
(period is equal to one divided by the frequency)
|
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To generate an US image, what is the order of activation for these system components: Pulsar, receiver, video display, beam former, memory or Pulsar, beam former, receiver, memory, video display or Beam former, pulsar, memory, video display, receiver or M
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Pulsar, beam former, receiver, memory, video display
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WHAT IS THE EQUATION FOR PULSE DURATION?
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# OF CYCLES IN PULSE* PERIOD
# OF CYCLES IN PULSE/ FREQUENCY
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LATA RESOLUTON IS USUALLY NOT AS GOOD AS LARRD RESOLUTION BECAUSE:
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US PULSES ARE WIDER THAN THEY ARE SHORT.
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