Finals Flashcards
Sound waves are:
a. electric
b. mechanical, transverse
c. spectral
d. longitudinal, mechanical
longitudinal, mechanical
The speed of US in soft tissue is closest to:
a. 1,540 km/sec
b. 1.54 km/msec
c. 1,500m/s
d. 1,540mm/sec
c. 1,500m/s
The frequency closest to the lower limit of US is:
a. 19,000kHz
b. 10,000MHz
c. 20,000 msec
d. 15,000Hz
d. 15,000Hz
Which is not an acoustic variable?
a. density
b. pressure
c. distance
d. intensity
d. intensity
The effects of soft tissue on US are called:
a. acoustic proliferation
properties
b. dynamic effects
c. acoustic propagation properties
d. biologic effects
c. acoustic propagation properties
Al of the following are true EXCEPT:
a. Two waves with identical frequencies must interfere constructively.
b. Constructive interference is associated with waves that are in-phase.
c. Out-of-phase waves interfere destructively
d. Waves of different frequencies may exhibit both constructive and destructive interference at different times.
a. Two waves with identical frequencies must interfere constructively.
Put in decreasing order:
a. deca
b. deci
c. micro
d. centi
Deca, deci, centi,micro
—–is the time to complete one cycle.
a. pulse duration
b. pulse period
c. period
d. duration period
c. period
Which of the
following sound waves is ultrasonic and least useful in diagnostic imaging?
a. 30 KHz
b. 8 MHZ
c. 8,000 Hz
d. 3,000 kHz
e. 15 Hz
a. 30 KHz
What is the frequency of a wave with 1 msec period?
a. 10,000 Hz
b.1000 KHz
c. 1 KHz
d. 1 MKz
c. 1 KHz
is the distance covered by one cycle.
a. pulse length
b. wavelength
c. cycle distance
d. cycle duration
b. wavelength
Which of the following is determined by the source and the medium?
a. frequency
b. period
c. propagation speed
d. range resolution
d. range resolution
Propagation speed = wavelength
a. pulse duration
b. period
e. number of cycles in the puls e
d. frequency
d. frequency
As a result of the
propagation speed increases.
a. increasing stiffness and increasing density
b. increasing stiffness and increasing elasticity
c. decreasing compressibility and decreasing den
sity
d. decreasing stiffness and decreasing density
c. decreasing compressibility and decreasing density
Put in decreasing order of propagation speed.
a. gas
b. liquid
c. solid
Solid, liquid, gas
If the frequency of US is increased from 0.77MHz to 1.54MHz, what happens to the wavelength?
a. doubles
b. halved
c. remains the same
d. 4 times greater
b. halved
A sound waves’ frequency is 10 MHz. The wave is traveling in soft tissue. What is its wavelength?
a. 0.15 mm
b. 1.54mm
c. 15.4mm
d. 0.77 mm
e. 10 MHz
a. 0.15 mm
If the frequency of an US wave
is doubled, what happens to the period?
a. doubles
b. halved
c. remains the same
d. 4 times greater
b. halved
If the frequency of US is increased from 0.77MHz to 1.54MHz, what happens to the propagation speed?
a. doubles
b. halved
c. remains the s a m e
d. 4times
c. remains the s a m e
The units of pulse repetition frequency are
a. per minute
b. msec
c. mm/us
d. MHx
b. msec
The time from the beginning of a pulse until its end is
a. period
b. pulse duration
c. puise length
d. PRF
b. pulse duration
What happens to the speed of sound in a medium when the
bulk modulus of the medium increases?
a. faster
b. slower
c. u n c h a n g e d
a. faster
—–resolution is determined by the spatial pulse length.
a . r a d i a l
b. image
c. axial
d. a n g u l a r
c. axial
a . r a d i a l
If a wave’s amplitude is doubled, what happens to the power?
a. nothing
b. halved
c. doubled
d. quadrupled
d. quadrupled
If the level of an acoustic variable ranges from 55 to 105, what is the amplitude?
a. 105
b. 50
c. 25
d. 55
c. 25
Power of sound has units of
a. dB
b. dB/cm
c. watts
d. watts/cm
c. watts
If the intensity of a sound beam remains unchanged while the beam area is reduced in half, what has happened to the power?
a. quadrupled
b. doubled
c. halved
d. unchanged
c. halved
Which of these intensities is smallest?
a. SATP
b. SPTP
C. SATA
C. SATA
The duty factor for continuous wave ultrasound is
а. 10.0
b. 1%
c. 1.0
d. 0 . 0 %
c. 1.0
What is the minimum value of the duty factor?
a. 10.0
b. 1%
c. 1.0
d. 0.0%
d. 0.0%
What are the units of intensity?
a. watts
b. decibels
c. watts/cm squared
d. d e c i b e l s
c. watts/cm squared
What happens to the speed of sound in a medium when the bulk modulus of the medium decreases?
a. faster
b. Slower
c . u n c h a n g e d
b. Slower
The units of attenuation
a r e ——- this is a ——–scale.
a. mm/cm, parametric
b. dB/m, multiplicative
c. none, relative
d. dB, logarithmic
d. dB, logarithmic
Sound intensity is decreased by 75%. How many decibels of attenuation is this?
‘a. 6dB
b. 9dB
c. 5dB
d. 10dB
a. 6dB
The fundamental frequency of a transducer is 2.5MHz. What
is the second harmonic frequency?
a. 1.25MHz
b. 4.5MHz
c. 5MHz
d. 5cm
c. 5MHz
A pulse emitted by a transducer and is traveling in soft tissue. The go-return time, or time-of-flight, of a sound pulse is 130
microseconds.
What is the reflector depth?
a. 10 cm
b. 10 mm
.c 10 m
d. 130 mm
e. 13 cm
a. 10 cm
If a 5MHz sound wave is traveling in the tissues listed below, which will have the longest wavelength?
a. Fat
b. Air
c. Muscle
d. Bone
d. Bone
If a 5MHz sound wave is traveling in the tissues listed below, which wil
l have the shortest wavelength?
a. Fat I
b. A i r
c. Muscle
d. Bone
b. A i r
What is the approximate attenuation coefficient of 1MHz US in soft tissue? “
a. 0.5dB/cm
b . 1 c m
c. 3dB/cm
d. 1dB
a. 0.5dB/cm
The rayl is the unit of:
a. intensity
b. reflectance
c. density
d . impedance
d . impedance
Impedance is the —-of —— and—–
a. product, propagation speed, density
b. sum, stiffness, density
c. quotient, stiffness, propagation speed
d. difference, attenuation, density
a. product, propagation speed, density
What are attenuation’s three components?
Reflection, Scattering, absorption
For soft tissue, the
approximate attenuation coefficient in dB/cm is equal to one-half
in
a. wavelength, mm
b. frequency, Hz
c. frequency, MHz
d. impedance, rayls
c. frequency, MHz
As the impedances of two
media become vastly different, the
a . reflection increases
b. transmission increases
c. refraction increases
d. absorption increases
reflection increases
The angle between an US pulse and the boundary between two media is 90°. What is this called?
a. direct incidence
b. oblique incidence
c. indirect incidence
d. orthogonal incidence
d. orthogonal incidence
The angle between an US pulse and the boundary between two media is 56°. This is called:
a. direct incidence
b. oblique incidence
c. indirect incidence
d. orthogonal incidence
b. oblique incidence
Refraction only occurs if there
a. normal incidence & different impedances
b. indirect intensity &different propagation speeds
c. oblique incidence & different propagation speeds
d. oblique frequency & identical impedances
c. oblique incidence & different propagation speeds
With normal incidence, what factors affect refraction of US?
a. propagation speeds
b. frequencies
c. attenuation coefficients
d. none of the above
d. none of the above
(True or False) With right angle incidence, reflections are always generated at a boundary if the propagation speeds of the media are different.
False
——–is a redirection of US in many directions as a result of a rough boundary between two media.
a. refraction
b. Rayleigh scattering
c . scattering
d. reflection
c . scattering
Which of the following tissues is most likely to create Rayleigh scattering?
a. red blood cells
b. muscle
c fat
d. bone
a. red blood cells
(True or False) With normal incidence the angle is 180°.
False
Under which of the follow
ing conditions is axial resolution improved?
a. decreased spatial pulse length
b. decreasedpulseamplitude
c. decreased imaging depth
d. decreased pixel size
e. decreased beam diameter
a. decreased spatial pulse length
Snell’s law describes physics
of
a. ultrasound
b. reflection
c. refraction
d. transmission
c. refraction
The most likely amount of
reflection at a boundary between soft tissues is:
a. 1%
b. 22%
с. 34%
d. 99%
a. 1%
The most typical amount of
transmission at a boundary in biologic media is:
a. 1%
b. 22%
c. 34%
d. 99%
d. 99%
Sound si traveling from medium 1to medium 2. Propagation speeds of My and M2 are 1,600m/s and 1,500m/s, respectively. There is oblique incidence.
a. angle of incidence › angle of reflection
b. angle of incidence = angle of reflection
c. angle of incidence <angle of reflection
b. angle of incidence = angle of reflection
(True or False) Doppler shifts always occur if the sound source and the receiver are in motion.
False
which of the following is associated with power mode doppler?
a. poor temporal resolution and flash artifact
b. lower sensitivity and good temporal resolution
.c high sensitivity and high frame rates
d. flash artifact and reduced sensitivity
e. good temporal resolution and flash artifact
a. poor temporal resolution and flash artifact
The Doppler shift is a measure of:
a. ratio of incident frequency to reflector frequency
b. sum of incident frequency & reflected frequency
c. difference between incident &reflected frequency
d. product of incident and reflected frequencies
c. difference between incident &reflected frequency
(True or False) The sonographer cannot change, directly or indire
ctly, the duty factor of an US machine.
False
Depth calibration of a machine measures 100mm spaced wires to be 90mm apart. Scanning reflectors 50 mm apart, what wil the machine calculate the distance to be?
a. 40mm
b. 45mm
.c 60mm
d. 65mm
b. 45mm
(True or False) There have not been biological effects from US found in the laboratory
False
In an analog scan converter, what component stores the image data?
a. computer memory
b. video tape recorder
c. dielectric matrix
d. none of the above
c. dielectric matrix
Which has the correct order?
mega-milli-kilo-micro-
a. 106 10-6 103 10-3
b. 10-6 106 102 10-3
с. 10 6 10-3 103 10-6
d. 106 10-6 103 10-4
c. 10 6 10-3 103 10-6
How many cm are
60 millimeters?
a. 600
b. 6
с. 0.6
d. 0.06
b. 6
(True or False) Lateral resolution is also called:
axial
azimuthal
longitudinal
range
azimuthal
Whcih has the corect units?
Freq, Speed, Intens, Atten
a. Hz mm/s joules dB/cm
b. mHz m/sec Wc/m2 DB
c. KH2 mm/us Wc/m3 dB/cm
b. mHz m/sec Wc/m2 DB
What increases patient exposure?
a. exam time
b. frequency
c. video taping
d. Wave length
a. exam time
Shadowing may result from high amount of reflection of US energy. Tor F
True
Where are harmonics created?
a, in the receiver
b. in the transducer
c. in the tissues
d. in the beam former
c. in the tissues
How is range ambiguity artifact eliminated?
a. lower the PRF
b. raise the PRF
.c increase the gain
d. use a lower frequency
transducer
a. lower the PRF
How is lateral resolution measured fi this test object is scanned from the top?
a. measure the distance from Ato E
b. measure length of line C and divide by 2
c. measure the length of line B
For Doppler, which incident angle results in no shift?
a. 180°
b. 90°
с. 0°
Which transducer would be best to image superficial structures?
a. small diameter, high frequency
b. small diameter, low frequency
.c large diameter, high frequency
d. large diameter, low frequency
a. small diameter, high frequency
A transducer with more than one active element is called:
a. multipurpose
b. annular
.c mechanical
d. array
d. array
How many bits are needed to represent 16 shades of grey?
a. 2
b. 3
c. 4
d. 5
c. 4
What information does Doppler shift provide?
a. flow
b. cardiac output
c. velocity
d. speed
c. velocity
A sound wave is a pressure wave made of compressions and rarefactions
true
A hydrophone is used to measure
a. velocity
b. frequency
c. intensity
d. phase
b. frequency
c. intensity
Images on videotape are stored using:
a. magic
b. magnetism
c. Paper
d. Computer Memory
b. magnetism
Circumferences may be measured in unit of:
a. cm
b. cm squared
c. cubic cm
d. cubits
a. cm
Decimal uses a base of 10, binary uses a base of
a. 1
b. 2
c. 5
d. 10
b. 2
If the frame rate increases and the lines per frame is unchanged, what else must happen?
a US speed increases .
b frequency increases
c.depth increases
d. depth decreases
d. depth decreases
Which of these cannot be performed by a sonographer?
a. adjust overall gain
b. clean VCR recording heads
c. clean pixels
d. adjust time gain compensation
c. clean pixels
which of the following is not a beam steering technique for a mechanical scan head
a. rotating wheel
b. phased beam
c. oscillating disc
d. oscillating mirror
b. phased beam
A system which was working well now does not display clear images in the far field. This may be a problem with the
a. transducer
b. receiver
c. monitor
d. scan converter
a. transducer
b. receiver
c. monitor
d. scan converter
How many decibels is related to a 90% decrease in imaging power?
a. -1 dB
b. -10 dB .
c -90 dB
d. -10dB
b. -10 dB
If the output of an US machine is calibrated in dB and the
the output is increased by 20db, increased
a. 100 times
b. 1,000,000 times
c. 20 times
d. 10 times
a. 100 times
- Which has the greatest amount of attenuation?
.a bone
b. fat
c. water
d. muscle
.a bone
Which of the following will result in the greatest number of shades of gray in a digital image display?
.a large pixels with many bits/pixel
b. small pixels with few bits/pixel
c. many VT lines per frame
d. high contrast
e. narrow dynamic range
.a large pixels with many bits/pixel
What is not the responsibility
of the sonographer?
a. clean the filters
b. adjust the recorder
c. adjust converter matrix
d. change paper
c. adjust converter matrix
With good images on the display but not on the printer, one should
a. increase the gain
b. check the scan head
c. check scan converter
d. adjust the recorder
d. adjust the recorder
To measure the US
beam - intensity, use a
a. calibrated hydrophone
b. lateral oscilloscope
c. water filled phantom
d. tissue equivalent phantom
a. calibrated hydrophone
When the US machine displays only strong reflecting objects and nothing else, the sonographer should
a. adjust far gain
b. increase output power
c. increase lateral resolution
d. adjust TGC
b. increase output power
Compression is used to
a. decrease the amplitude
b. decrease the range of
amplitudes
c. decrease the range of frequencies
b. decrease the range of
amplitudes
Reject is used to
a. adjust the appearance of highly reflective objects
b. adjust the appearance of lowly reflective objects
c. improve axial resolution d. improve digital scan
conv
erter sensitivity
b. adjust the appearance of lowly reflective objects
If a reflector is moved twice as far away from the transducer, how will this affect the time- of-flight of a sound pulse?
a. quadruple it
b. double it
c. no change
d. halve it
b. double it
A single element transducer is focused
a. by the manufacturer
b. cannot be focused
c. by increasing power
d. by the sonographer
a. by the manufacturer
An US machine has a digital
scan converter but has an analog input signal. The machine needs to have a
a. hybrid multiplexer
b. m o d e m
c. analog to digital converter
d. digital monitor
c. analog to digital converter
