Part 4 Flashcards
Sound waves are: A. Electric B. Mechanical, transverse C. Spectral D. Longitudinal, mechanical
D.
The speed of US in soft tissue is closest to: A. 1.540 km/sec B. 1.54 km/section C. 1,500 m/s D. 1,540 mm/sec
C
The frequency closest to the lower limit of US is: A. 19,000 kHz B. 10,000 MHz C. 20,000 msec D. 15,000 Hz
D
Which is NOT an acoustic variable? A. Density B. Pressure C. Distance D. Intensity
D
The effects of soft tissue on US are called: A. Acoustic proliferation properties B. Dynamic effects C. Acoustic propagation properties D. Biological effects
Acoustic propagation properties
All 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 difference times
A
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
Period
Which of the following sound waves is US and least useful in diagnostic imaging? A. 30 KHz B. 8 MHz C. 8,000 Hz D. 3,000 kHz E. 15 Hz
A.
What is the frequency of a wave with 1 msec period? A. 10,000 Hz B. 1,000 kHz C. 1 kHz D. 1 MHz
C.
\_\_\_\_\_\_\_\_\_\_ is the distance covered by one cycle. A. Pulse length B. Wavelength C. Cycle distance D. Cycle duration
B
Which of the following is determined by the source and medium? A. Frequency B. Period C. Propagation speed D. Range resolution
D.
Propagation speed = \_\_\_\_\_\_\_\_ x wavelength A. Pulse duration B. Period C. Number of cycles in pulse D. Frequency
D
As a result of __________ the propagation speed increases.
A. Increasing stiffness & increasing density
B. Increasing stiffness & increasing elasticity
C. Decreasing compressibility & decreasing density
D. Decreasing stiffness & decreasing densit
C.
Put in decreasing order of propagation speed.
A. Gas
B. Liquid
C. Solid
Solid, liquid, gas
If the frequency of US is increased from 0.77 MHz to 1.54 MHz, what happens to the wavelength? A. Doubles B. Halved C. Remains the same D. 4 times greater
B.
A sound wave's frequency is 10 MHz. The wave is traveling in soft tissue. What is its wavelength? A. 0.15 mm B. 1.54 mm C. 15.4 mm D. 0.77 mm E. 10 MHz
A.
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 0.77 MHz to 1.54 MHz, what happens to the propagation speed? A. Doubles B. Halved C. Remains the same D. 4 times greater
Remains the same
The units of pulse repetition frequency are: A. Per minute B. Msec C. Mm/us D. MHx
A.
The time from the beginning of a pulse until its end is \_\_\_\_\_\_\_\_\_\_? A. Period B. Pulse duration C. Pulse length D. PRF
Pulse duration
What happens to the speed of sound in a medium when the bulk modules of the medium increases?
A. Faster
B. Slower
C. Unchanged
A.
\_\_\_\_\_\_\_\_\_\_ resolution is determined by the spatial pulse length. A. Radial B. Image C. Axial D. Angular
Radial or axial
If a wave's amplitude is doubled, what happens to the power? A. Nothing B. Halved C. Doubled D. Quadrupled
D.
Power of sound has units of: A. dB B. dB/cm C. Watts D. Watts/cm2
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
Sata
The duty factor for continuous wave US is: A. 10.0 B. 1% C. 1.0 D. 0.0%
1.0
What is the minimum value of the duty factor? A. 10.0 B. 1% C. 1.0 D. 0.0%
0.0
What are the units of intensity?
A. Watts
B. Decibels
C. Watts/cm2
c.
What happens to the speed of sound in a medium when the bulk modulus of the medium decreases?
A. Faster
B. Slower
C. Unchanged
B
The units of attenuation are \_\_\_\_\_\_\_\_\_\_; this is a \_\_\_\_\_\_\_\_\_\_ scale. A. mm/cm, parametric B. dB/m, multiplicative C. None, relative D. dB, logarithmic
Db, logarithmitic
Sound intensity is decreased by 75%. How many decibels of attenuation is this? A. 6 dB B. 9 dB C. 5 dB D. 10 dB
A.
The fundamental frequency of a transducer is 2.5 MHz. What is the second harmonic frequency? A. 1.25 MHz B. 4.5 MHz C. 5 MHz D. 5 cm
5 Mhz
A pulse is 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
10 cm
f a 5MHz sound wave is traveling in the tissues listed below, which will have the shortest wavelength? A. Fat B. Air C. Muscle D. Bone
Air
If a 5 MHz sound wave is traveling in the tissues listed below, which will have the longest wave? A. Fat B. Air C. Muscle D. Bone
D.
Impedance is the _________ of __________ and __________.
A. Product, propagation speed, density
B. Sum, stiffness, density
C. Quotient, stiffness, propagation speed
D. Difference, attenuation, density
Product, prop speed, density
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 degrees. What is this called? A. Direct incidence B. Oblique incidence C. Indirect incidence D. Orthogonal incidence
D.
The angle between an US pulse and the boundary between two media is 56 degrees. This is called: A. Direct incidence B. Oblique incidence C. Indirect incidence D. Orthogonal incidence
Oblique incidence
Refraction only occurs if there are:
A. Normal incidence & different impedances
B. Indirect intensity & different propagation speeds
C. Oblique incidence & different propagation speeds
D. Oblique frequency & identical impedances
C.
With normal incidence, what factors affect refraction of US? A. Propagation speeds B. Frequencies C. Attenuation coefficients D. None of the above
None of the above
\_\_\_\_\_\_\_\_\_ 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
Scattering
Under which of the following conditions is axial resolution improved? A. Decreased spatial pulse length B. Decreased pulse amplitude C. Decreased imaging depth D. Decreased pixel size E. Decreased beam diameter
A.
Snell's law describes physics of \_\_\_\_\_\_\_\_\_\_. A. Ultrasound B. Reflection C. Refraction D. Transmission
C
The most likely amount of reflection at a boundary between soft tissues is: A. 1% B. 22 % C. 34% D. 99%
A
The most typical amount of transmission at a boundary in biological media is: A. 1% B. 22% C. 34% D. 99%
99%
Sound is traveling from medium 1 to medium 2. Propagation speeds of M1 and M2 are 1,600 m/s and 1,500 m/s, respectively. There is normal incidence.
A. Angle of incidence > angle of reflection
B. Angle of incidence = angle of reflection
C. Angle of incidence < angle of reflection
B
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.
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.
Depth calibration of a machine measures 100 mm spaced wires to be 90 mm apart. Scanning reflectors 50 mm apart, what will the machine calculate the distance to be? A. 40 mm B. 45 mm C. 60 mm D. 65 mm
45 mm
What increases patient exposure? A. Exam time B. Frequency C. Video taping D. Wavelength
Exam time
Where are harmonics created? A. In the receiver B. In the transducer C. In the tissues D. In the beam former
C.
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.
For Doppler, which incident angle results in no shift? A. 180 degrees B. 90 degrees C. 0 degrees D. 45 degrees
B
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.
A transducer with more than one active element is called: A. Multipurpose B. Annular C. Mechanical D. Array
D.
How many bits are needed to represent 16 shades of grey? A. 2 B. 3 C. 4 D. 5
4.
What information does Doppler shift provide? A. Flow B. Cardiac output C. Velocity D. Speed
C.
A hydrophone is used to measure: A. Velocity B. Frequency C. Intensity D. Phase
Frequency or intensity
Images on videotape are stored using: A. Magic B. Magnetism C. Paper D. Computer memory
Magnetism
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.
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
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.
Which has the greatest amount of attenuation? A. Bone B. Fat C. Water D. Muscle
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 TV lines per frame D. High contrast E. Narrow dynamic range
A.