test 1 Flashcards
the brightness of a dot corresponds to the ___ of the echo
a. location
b. speed
c. strength
d. angle
strength
a rectangular image display would be seen when using a ___ transducer
a. sector
b. vector
c. convex
d. linear
linear
the location of each dot corresponds to the ____ of the echo to return
a. strength
b. time
c. pulse
d. frequency
time
the method in which each pulse originates from the same starting point is termed a ____ image.
a. sector
b. linear
c. convex
d. none of the above
sector
echoes produced by _____ objects have a different ____ than the pulses sent into the body
a. stationary; frequencies
b. stable; directions
c. moving; frequencies
d. moving; echoes
moving; frequencies
doppler ultrasound detects movement of ____
a. tissue
b. blood
c. A and B
D. none of the above
a and b
All of the following are doppler display instruments except:
a. spectral analysis
b. strip chart
c. color
d. transducer
transducer is not a display instrument
the doppler effect is change in echo:
a. frequency
b. strength
c. amplitude
d. direction
frequency
the motion that produces the Doppler effect is that of the ______
a. TGC
b. Display
c. reflector
d. sound beam
reflector
a ______ scan is shaped like a slice of pie
a. sector
b. convex
c. linear
d. curvilinear
sector
sonography is medical anatomic imagining using _____-_____ technique
a. starting point
b. pulse echo
c. vertical parallel
d. transducer instrument
pulse ehco
3D imaginig requires many adjacent tissue ______ _____ to build the imagine
a. moving objects
b. frequency shifts
c. cross sections
d. ultrasound pulses
cross sections
one pulse of ultrasound generates a single scan line as it travels through a tissue
a. ture
b. false
true for now
ultrasound transducers can only generate ultrasound pulses
a. true
b. false
false beacuse they can also receive ultrasound pulses
ultrasound transducers can deteremine the character of blood flow
a. true
b. false
true
_______ is the number of complete cyles per second
a. wavelenght
b. period
c. frequency
d. propogation speed
frequency
sound requires a _____ through which to travel
a. medium
b. pressure
c. vaccum
d. wave
medium
the follwoing are all ultrasound frequencies expect:
a. 30,000 Hz
b. 250 kHz
c. 15 kHz
d. 0.30 MHz
15 kHz beacuse the range is
<20 Khz
<20,000 Hz
<2 mhz
0.30 is 300,000 Hz
if frequency increases, period will ______
a. increase
b. decrease
c. remain unchanged
d. none of the above
decrease
wavelength is the _______ over which one cycle occurs
a. time
b. distance
c. area
d. all of the above
distance
propogation speed is the speed at which a wave _____ through a medium.
a. cycles
b. speckles
c. travels
d. reflects
travels
stiffer media have ______sound speeds
a. lower
b. higher
c. stiffness doesnt change the propogation speed
d. sound cannot propogate through stiffer media
higher
frequency _______ wavelength
a. is directly proportional to
b. is inversly proportional to
c. is equal to
d. has no bearing on
is inversly proportional to
propagation speed is primarily deteremined by the ______ of the medium.
a. density
b. thickness
c. stifness
d. water
stiffness
ultrasound pulses contain a range of frequencies called the ______
a. fundamental frequencies
b. duty factor
c. pulse repetition frequencies
d. bandwidth
bandwidthe
pulsed ultrasound consists of _____ seperated by _____ of time
a. frequencies; cycles
b. pulses; cycles
c. pulses; gaps
d. cycles; pulses
pulses; gaps
pulse repetition frequency is the _____ of pulses occuring in 1 second
a. speed
b. number
c. type
d. cycle
number
regions of lower pressure and density are called _______.
a. compressions
b. rarefactions
c. longitudinal waves
d. acoustic variables
rarefactions
period is the _____ it takes for one ____ to occur
a. time; cycle
b. time; wavelenght
c. frequency; cycle
d. time; pulse
time; cycle
_______ is (are) the even and odd multiples of the fundamental frequency
a. bandwidth
b. harmonics
c. mechanical waves
d. side lobes
harmonics
propagation speed is higher in _____ than soft tissue
a. lung
b. bone
c. water
d. fat
bone
doppler ultrasound pulses are typically ___ cycles long
a. 2 or 3
b. 12 to 30
c. 5 to 20
d. 5 to 30
5 to 30
the percentage of time that pulsed ultrsound is on is called _____
a. pulse repetition period
b. duty factor
c. period
d. spatial pulse length
duty factor
the rate at which energy passes through a unit area is called _____
a. amplitude
b. power
c. attenutation
d. intensity
intensity
as sound travels, th reduction in amplitude and intensity of the wave is called _______
a. scattering
b. attenuation
c. absorption
d. reflection
attenutation
the wavelength of 3 MHz ultrasound in soft tissue is _____mm.
a. 510
b. 5.1
c. 0.51
d. 4.6
0.51
wavelenth= 1.54/ frequency
what would the frequency be for a 0.22mm wavelength in soft tissue?
a. 5.0 MHz
b. 7.0 Mhz
c. 7.5 mhZ
d. 3.5 Mhz
7.0 Mhz
what is the period of a 5.0 MHz transducer in soft tissue?
a. 0.2 us
b. 0.02 us
c. 3.1 us
d. 0.2 sec
0.2 us
T= 1/F
what is the pulse duration of a four-cyle pulse in a period of 0.5us?
a. 0.2 us
b. 2.0 us
c. 1.25 us
d. 0.125 us
2.0 us
PD= T x # cycles
the spatial pulse lentgh in soft tissue for a three-cycle pulse, using a frequency of 5.0 MHz, is ___–
a. 0.6 mm
b. 6.0mm
c. 0.9mm
d. 9.0mm
0.9
SPL= wavelentgh x # cycles
if the wavelength is 0.5mm, the spatial pulse length for a four-cycle pulse is
a. 0.2 mm
b. 8.0 mm
c. 0.8mm
d. 2.0 mm
2.0 mm
SPL= wavelength x # cycles
the avergae propagation speed in human soft tissue is ______.
a. 1.54 cm/us
b. 1.54 mm/ us
c. 15.4 m.sec
d. none of the above
1.54 mm/us
if you employ a 7.5 MHz transducer, what is the wavelength of the sound in soft tissue?
a. 0.11mm
b. 0.21mm
c. 0.025mm
d. 1.1 mm
0.21mm
if you switch to a lower frequency for penetration, the wavelength of the transducer will ______
a. remain unchanged
b. decrease
c. increase
d. double
increase
20 KHz is equal to ____Hz
a. 200
b. 2,000
c. 20,000
d. 200,000
20,000
500 Hz is equal to _____ kHz.
a. 5
b. 50
c. 5,000
d. 0.500
0.500
1Khz= 1000Hz
what is the attenuation coefficient for a 5.0 MHz transducer in soft tissue
a. 0.25 dB/cm
b. 0.1 dB/cm
c. 2.5 dB/cm
d. 10.0 dB/cm
2.5 dB/cm
attenuation coefficient= 1/2x frequnecy
at what depth would a 3.0 Mhz transducer have an attenuation of 9 Db.
a. 6.0 mm
b. 0.6 cm
c. 6.0 cm
d. 0.6mm
6.0 cm
1/2 x 3= 1.5 dB/cm
then 9/ 1.5 = 6 cm
the attenuation of a 5.0 MHz transducer at a depth of 4cm is ___dB.
a. 1.6 db
b. 10.0 db
c. 16.0 db
d. 20.0 db
10.0 db
1/2 x 5= 2/5 dB/cm
2.5 x 4= 10 db
what is the attenuation of 7.5 MHz transducer at a dpeth of 20mm?
a. 7.5 db
b. 5.0 db
c. 0.53 db
d. 75.0 db
7.5 db
20mm= 2 cm
1/2 x 7.5= 3.75 db/cm
3.75 x 2= 7.5 db
if beam power increases, intensity will ____.
a. increase
b. decrease
c. double
d. remain unchanged
increase
if beam area decreased, the intensity will _____
a. decrease
b. remain unchanged
c. increased
d. quadruple
increased
attenutation increases with increasing _____
a. wavelength
b. frequency
c. power
d. pressure
frequency
for perpendicular incidence, the incidence angle is ____ degress
a. 50 degrees
b. 10 degrees
c. 90 degress
d. 0 degrees
90
the pulse repetition frequency is the number of pulses that occur in a ______
a. microsecond
b. second
c. millisecond
d. pulse
second
calculate the pulse duration fo a 3.0 MHz transducer in soft tissue with a four-cycle pulse
a. 1.2 us
b. 1.3 us
c. 12.0 us
d. 13.0 us
1.3 us
PD= T x # of cycles
pulse duration will increase with all of the following expect:
a. period
b. number of cycles in the pulse
c. frequency
d. none of the above
frequency
continous wave doppler has a duty factor of ___ %
a. 1
b. 0.10
c. 100
d. 10
100
the duty factor will increae with all of the following expect:
a. pulse repetition frequency
b. pulse duration
c. period
d. none of the abov
pulse repetition frequency
what is the spatial pulse length of a four-cycle pulse with a wavelentgh of 0.1mm?
a 4.0mm
b. 0.4cm
c. 0.4mm
d. 40.0mm
0.4mm
SPL= wavelenght x #of cycles
the spatial pulse length will increse with all of the following expect:
a. wavelenght
b. frequency
c. number of cycles in the pulse
d. none of the above
frequency
the attenuation coefficient for soft tissue using 10 MHz transducer is ____
a. 5 db/cm
b. 5 db/mm
c. 10 db/cm
d. 10 db/mm
5 db/cm
impedance is equal to the denisty multipled by _____
a. propagation speed
b. wavelength
c. path length
d. stiffness
propagation speed
the unit for impedance is ___
a. W/cm^2
b. db/cm
c. watt
d. rayle
rayl
the even harmonics of 2 Mhz are ____-MHz
a. 2,4,6
b. 4,8,12
c. 2,4,8
d. 4,6,8
4,8,12
in perpendicular incidence, what is the intensity reflection coefficient for impedances of 45 and 55 rayls?
a. 0.001
b. -0.01
c. 0.01
d. 0.10
0.01
snells law relates the ___beam direction to the incident beam direction and the speeds of sound in the two materials forming the inerface
a. scattering
b. rarefaction
c. reflected
d. transmitted
transmitted
snells law is all about refraction
the distance to the relflector in soft tissue with a round-trip time of 39 us is
a. 30 cm
b. 60 mm
c. 60 cm
d. 30 mm
30mm
13 us/cm
39us / 13 us/cm= 3 cm or 30 mm
what does -3 db of attenuation mean?
a. one half of the original intensity
b. one third of the orginal intensity
c. 3 decibels more than the original intensity
d. increasing amplitude
one half of the orignial intensity
3db= 50%
the attenutation of 5 MHz transducer in soft tissue would be ____ db at 2
a. 20.0
b. 5.0
c. 10.0
d. 1.25
5.0
continous wave sound is described by all of the terms below expect:
a. pulse duration
b. frequency
c. wavelength
d. propogation speed
pulse duration
attenuation encompasses:
a. absorption
b. scattering
c. reflection
d. all of the above
all of the above
what units are used to quantify attenution?
a. it is unitless
b. db/cm
c. db
d. rayls
db
impedance increases when ___ increases
a. density
b. propagation speed
c. A or B
d. none of the above
A or B
for perpendicular incidence and equal impedances between media, there is no ____ and the _____ equals the incident intensity
a. transmission; reflected
b. reflection; transmitted
c. transmission; transmitted
d. reflection;reflected
reflection; transmitted
the distance to a reflector in soft tissue is 15 cm. what is the round-trip time to this depth?
a. 19.5 us
b. 195.0 us
c. 1.15 us
d. 11.5 us
195.0 us
13 us/cm x 15= 195 us
if the pulse duration is 3 us and the pulse repetition period is 350 us, the duty factor is ______%
a. 0.86
b. 8.6
c. 0.086
d. 1.16
DF= PD/ PRP
= 0.0086x 100=
0.86
in oblique incidence the ____ and ___ angles are always equal
a. transmitted; reflected
b. normal; transmitted
c. incidence; reflection
d. incidence; transmitted
incidence; reflection
if an echo returns 104 us after a pulse was emitted by a transducer. at what depth is the structure that produced the echo located?
a. 0.8 mm
b. 80.0 cm
c. 8.0 mm
d. 8.0 cm
8.0 cm
104 us/ 13 us/cm= 8cm
intensity is equal to the power of a wave divided by the _____ over which the power is spread
a. diameter
b. radius
c. area
d. width
area
the propagation speed for a round-trip time of 39 us through soft tissue is _____mm/us
a. 1540.0
b. 15.4
c. 1.45
d. none of the above
none of the above it is 1.54mm/us
____ is the dominant factor contributing to attenuation of ultrasound in soft tissue
a. absorption
b. backscattering
c. reflection
d. range
absorption
interfaces that scatter ultrasound energy, are usually considered to be those that are equal to or smaller than the wavelenght
a. true
b. false
true, really small thing and irregular surfaces scatter
sound can travel through air, lung, bone and a vaccum
a. true
b. false
false
sound is a mechanical longitudinal wave
a. true
b. false
true
stiffer media have higher sound speeds
a. true
b. false
true
the propagation speed in soft tissue is considered a constant
a. true
b. false
true
duty factor is unitless
a. true
b. false
true
attenuation increases with an increase in wavelength
a. true
b. false
false because an increase in wavelentgh means a decrease in frequency so therefore a decrease in attenuation decreases
spatial avergae is the average intensity at the beam center
a. true
b. false
false, it is the avergae of the whole beam
when frequency increases, the period decreases
true
the propagaion speed in soft tissue is 1.54 m/s
false
1.54mm/us or 1,540 m/s
a cycle is one complete variation in pressure
true, cycle has high and low pressure
the shorter the pulse, the broader the bandwidth
True
