Comprehensive Exam SPI
Refraction ONLY occurs if there is : ________ incidence & ________ propagation speeds.
Oblique, Different
Component of a transducer that changes electrical to mechanical and mechanical back to electrical energy is known as ______.
PZT
What determines the frequency of a sound beam from a pulsed transducer?
PZT thickness
Unit for pressure = _______
Pascals (Pa)
______ is an advantage in coded excitation.
Penetration
Hertz is another way of saying ____ _______.
Per second
4 types of NORMAL INCIDENCE: "porn"
Perpendicular, Orthogonal, right angle, ninety degrees
Consolidation of many images into a single frame best describes _______.
Persistence
Which transducer would be best to image superficial structures? _____ diameter, ____ frequency
Small diameter, high frequency
Put in decreasing order of propagation speed:
Solid - liquid - gas
Intensity description for the lowest value=
Spatial Average Temporal Average (SATA)
Intensity description that is most important for thermal bioeffects=
Spatial Peak Temporal Average (SPTA)
Intensity description for the highest value=
Spatial Peak Temporal Peak (SPTP)
The creation of an image by scanning from different angles best describes _______ _______.
Spatial compounding
The more pixels per inch the better is the ______ ______.
Spatial resolution
______ artifact has a grainy appearance and is caused by the interference effects of scattered sound.
Speckle
The interaction of microscopic bubbles and ultrasound form the basis for cavitation bioeffects. Which of the following forms of cavitation are most likely to produce micro streaming in the intracellular fluid and shear stresses?
Stable cavitation
Enhancement, multi path and side lobes result in ________.
Artifact
When can the patient revoke consent
At any time
When may a patient revoke their consent to be treated?
At any time
What is another name for a longitudinal resolution?
Axial; depth
Which of the following and improves the signal-to-noise ratio?
Frame averaging
If a manufacturer changed the lines per frame and kept the imaging depths the same, what else would change?
Frame rate
Propagation speed = _________ x wavelength
Frequency
_______ affects penetration and axial resolution (image quality).
Frequency
Which of the following does NOT change temporal resolution?
Frequency compounding
For soft tissue, the approximate attenuation coefficient in dB/cm is equal to one-half _______ in ______.
Frequency, MHz
The region from the transducer to the minimum beam cross-sectional area is the _______ zone.
Fresnel
The rayl is the unit of _________.
Impedance
Where are harmonics created?
In the tissues
All of the following statements regarding in vitroBio effects are true EXCEPT
In vitro bioeffects conclusions are clinically relevant
Fill in of an anechoic structure such as a cyst is known as all of the following EXCEPT: Partial volume artifact Slice thickness artifact Section thickness artifact Ghosting artifact
Ghosting artifact
Which of the following clinical modalities has the lowest output and intensity?
Grayscale imaging
At the focus, the beam diameter is _______ the transducer diameter
Half
If the intensity of a sound beam remains unchanged while the beam area is reduced in half, what has happened to the power?
Halved
Under which circumstance is the mechanical index the lowest? _____ frequency and ____ power
High frequency and low power
What measures the output of a transducer?
Hydrophone
If we increase the frequency, the near zone length is _______
Increase
When the ultrasound machine displays only strong reflecting objects and nothing else, the sonographer should:
Increase output power
If the frequency is decreased, the numerical value of the radial resolution is __________.
Increased
If the transducer aperture increases, the lateral resolution at its smallest dimension is _______.
Increased
All of the following will improve temporal resolution EXCEPT:
Increased line density
As frequency increases, scattering _______.
Increases
As frequency increases, the attenuation coefficient _______.
Increases
Which is NOT an acoustic variable?
Intensity
________ is the concentration of the power in a beam.
Intensity
A hydrophone is used to measure ______ and ______.
Intensity and frequency
The Curie temperature has which affect
The ferroelectric material is depolarized
(T or F) A sound wave is a pressure wave made of compressions and rarefactions.
True
Which of the following best describes a sound beam? A collection of mechanical vibrations in the form of ________ and _______
compressions and rarefactions
Lateral resolution is also called: axial (T or F) azimuthal (T or F) longitudinal (T or F) range (T or F)
false, true, false, false
The fraunhofer is known as the _____ zone.
far zone
The angle between an ultrasound pulse and the boundary between two media is 90°. what is this called?
orthogonal incidence
The units of pulse repetition frequency are:
per minute
_______ is the time to complete one cycle.
period
The production of a voltage from the application of a pressure is called _______.
piezoelectricity
What is the production of deformation from voltage called?
piezoelectricity
As the impedances of two media become vastly different, the __________ increases.
reflection
________ pulses create more accurate images
short
Which of these boundaries will create the weakest reflection? air-lung air-soft tissue air-blood soft tissue-blood
soft tissue-blood
What happens to the speed of sound in a medium when the Bulk modulus of the medium DEcreases?
speed of sound decreases
What happens to the speed of sound in a medium when the bulk modulus of the medium INcreases?
speed of sound increases
While propagating, a sound wave is refracted. Finally, it returns to the transducer.The system processes the sound waves as if it has traveled in a _________ _____ , reflected and returned.
straight line
A transducer with more than one active element is called ______.
Array
The units of attenuation are ______; this is a ______ scale.
dB (decibels), logarithmic
What units report the *relative* bigness of a sound beam?
dB - decibels
And ultrasound system is set at 0 dB and is transmitting at full intensity. What is the output power when the system is transmitting at 10% of full intensity?
-10 dB
What would be the brightest B-mode spot when scanning the following?
********
How is lateral resolution measured if this test object is scanned from the top?
*****************
In ultrasound system is set at 0 dB and is transmitting at full intensity. What is the output power when the system is transmitting at 50% of full intensity?
-3 dB
All of the following are true of normal cavitation EXCEPT: -Harmful bioeffects are commonly observed -Only a 10% increase in pressure is needed to convert to this from stable cavitation -It is also known as inertial cavitation -Temperatures in the thousands of degrees are created -Is consistent with shockwaves
-Harmful bioeffects are commonly observed
A sound wave strikes a boundary at normal incidence. The impedances of the two media are identical. What percentage of the sound wave is refracted?
0% (Remember refraction requires oblique incidence)
The MINIMUM value of the duty factor is __.__%
0.0%
Which of the following is the best lateral resolution? 0.5 cm 5 cm 0.06 cm 2 cm
0.06 cm
According to the AIUM statement on bioeffects, there have been no confirmed bioeffects below intensities of __.__ watts per square cm SPTA.
0.1
A sound wave's frequency is 10 MHz. The wave is traveling in soft tissue. What is its wavelength?
0.15 mm
If 300,000 cycles occur in a second, what is the waves frequency?
0.3 MHz
If this spatial pulse length is 10 mm, the axial resolution is __.__ cm.
0.5 cm
What is the approximate attenuation coefficient of 1 MHz ultrasound in soft tissue?
0.5 dB/cm
Attenuation of ultrasound in soft tissue is closest to __.__ dB/cm/MHz
0.6 dB/cm/MHz
In soft tissue, sound with a frequency of 2 MHz has a wavelength of _.____ mm
0.77 mm
What are typical clinical Doppler frequencies?
1 - 10,000 Hz
In soft tissue every 13 µs of go-return time means the reflector is _____ deeper in the body.
1 cm
What is the frequency of a wave with 1 msec period?
1 kHz
The relative output of an ultrasound instrument is calibrated in decibels and operator increases the output by 60 dB.The beam intensity is increased by __________ times.
1 million times
The most likely amount of reflection at a boundary between soft tissues is __%
1%
This speed of ultrasound in soft tissue is closest to:
1,500m/s
Average speed of all sound (regardless of frequency) in biologic or "soft tissue" =
1,540 m/s = 1.54 km/s = 1.54 mm/µs
The duty factor for continuous wave ultrasound is __.__%
1.0%
In soft tissue, sound with a frequency of 1 MHz has a wavelength of _.____ mm
1.54 mm
The propagation speed of ultrasound in the AIUM test object is _________.
1.54 mm/µs
____ bits are needed to represent 1024 gray shades.
10
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 µs (microseconds). What is the reflector depth?
10 cm
Biologic effects have not been documented below what intensity (SPTA)>
100 mW/cm²
Which has the correct order for this: mega-milli-kilo-micro
10⁶ - 10⁻³ - 10³ - 10⁻⁶
Know that 0.000001 is _____ or _____.
10⁻⁶ or micro
A Doppler exam is performed with a 5 MHz probe and a PRF of 15 kHz. Which of these Doppler shifts will create aliasing?
14 kHz
The frequency closest to the lower limit of ultrasound is:
15,000 Hz
Decimal uses a base of 10, binary uses a base of ___.
2
What is the range of frequencies created by medical diagnostic Doppler transducers?
2 - 10 MHz
What is the most typical Doppler shift measured clinically?
2 kHz
The distance to a target is doubled. The time-of-flight for a pulse to travel to the target and back is ___ times.
2 times
Average speed of sound through bone =
2,000 - 4,000 m/s
An object is located at a depth of 10 cm. The imaging depth is 7 cm. At what depth will a reflection from the object appear on the image?
3 cm
Which of the following is NOT pre-processing?
3-D rendering
Which of the following sound waves is ultrasonic and LEAST useful in diagnostic imaging?
30 KHz
Average speed of sound through air =
330 m/s
How many bits are needed to represent 16 shades of grey?
4
Depth calibration of a machine measures 100 mm spaced wire to be 90 mm apart. Scanning reflectors 50 mm apart, what will the machine calculate the distance to be?
45 mm
The fundamental frequency of a transducer is 2.5 MHz. What is the second harmonic frequency?
5 MHz
The boundary soft tissue-bone creates __% reflection (attenuation).
50%
How many cm are 60 mm?
6
____ data bits are needed to represent 46 gray shades.
6
Sound intensity is DEcreased by 75%.How many decibels of attenuation is this?
6 dB (decibels)
What Doppler angle is most inaccurate? 15-30 degrees 30-45 degrees 45-60 degrees 60-75 degrees
60-75 degrees
An ultrasound wave travels through two media and has attenuation of 3 dB in the first and 5 dB in the second. What is the total attenuation?
8 dB
The impedance of tissue is 3 x 10⁵ rayls and for the PZT crystal is 6 x 10⁶ rayls. What is the best impedance for the matching layer?
9.5 x 10⁵
For Doppler, which incident angle results in no shift?
90°
The boundary soft tissue-air creates __% reflection (attenuation).
99%
The most typical amount of transmission at a boundary in biologic media is __%
99%
The boundary soft tissue-soft tissue creates __% reflection (attenuation).
< 1%
Post processing occurs when the image enters the _______ but before display
A/D converter
Which is not a part of a transducer?
A/D converter
Bone attenuates sound by _________.
Absorption
Reflection w/ normal incidence occurs always if the two media at the boundary have different ______ ______.
Acoustic impedances
The affects of soft tissue on ultrasound are called:
Acoustic propagation properties
With good images on the display but not on the printer, one should:
Adjust the recorder
If a 5 MHz sound wave is traveling in the tissues listed below, which will have the SHORTEST wavelength?
Air (Speed of sound in air is the lowest)
Put in increasing order of propagation speed:
Air, water, bone
The dynamic range is the ratio of the smallest to largest ________ that a system can process without distortion.
Amplitude
In ultrasound machine has a digital scan converter but has an analog input signal.The machine needs to have a:
Analog to digital converter
Which has the greatest amount of attenuation?
Bone
If a 5 MHz sound wave is traveling in the tissues listed below, which will have the LONGEST wavelength?
Bone (speed of sound in bone is the highest)
A quality assurance program is needed:
By all labs
To measure the ultrasound beam intensity, use a _______ ______.
Calibrated hydrophone
You encounter a patient that does not speak English. Which of the following is best to obtain informed consent?
Call for a hospital interpreter
Which of these cannot be performed by a sonographer?
Clean pixels
Improved contrast resolution is one of the advantages of ________ _______.
Coded excitation
_______ _______ & ____ _____ & ______ the PRF will eliminate range ambiguity artifact.
Coded excitation; Imaging deeper; lowering the PRF
The process of reducing the difference between the smallest and largest voltages is called _______.
Compensation
What is the name of the receiver function that corrects for attenuation?
Compensation
___________ are areas of INCREASED pressure and density.
Compressions
A transducer ______ one form of _____ into another.
Converts; Energy
When the sound source and the receiver are not moving directly towards or away from each other, _______ of the angle between them enters into the calculation of Doppler shift.
Cosine
What is the standard for communication between medical imaging computers?
DICOM
If we increase the transducer diameter, the beam diameter in the far zone is _______.
Decreased
Under which of the following conditions is the lateral resolution improved? Decreased _______ _______
Decreased beam diameter
Under which of the following conditions is axial resolution improved?
Decreased spatial pulse length
If the lines per frame is increased while the imaging depth is unchanged in the frame rate ______.
Decreases
As a result of _______ the propagation speed increases.
Decreasing compressibility & decreasing density
Rectification and smoothing are components of ________.
Demodulation
Propagation speed is determined by _____ and _____.
Density and elasticity
Impedance is the product of ________ and ______.
Density and propagation speed
Which of the following best describes the features of a sound wave and medium that determine the speed of sound in the medium?
Density of the medium and stiffness of the medium
If the frame rate increases and the lines per is unchanged, what else must happen?
Depth decreases
The Doppler shit is the ______ of two frequencies.
Difference
Changing which of the following would not cause any change in a hardcopy image output?
Display brightness and contrast
If the intensity is increased by 3 dB (decibels), it _______.
Doubles
What is the fraction of time that a transducer is transmitting?
Duty factor
(T or F) A sonographers education ends when they become registered.
False
(T or F) Axial resolution is affected by focusing.
False
(T or F) Doppler shifts always occur if the sound source and receiver are in motion.
False
(T or F) Doppler shifts always occur if the source and Observer are in motion relative to each other and the angle between the motion and the sound beam is 90°
False
(T or F) Doppler shifts are always created when the source and receiver are in motion relative to each other.
False
(T or F) Increasing the frequency increases the penetration depth.
False
(T or F) Sonographers cannot affect a patients exposure to a acoustic energy.
False
(T or F) The digital scan converter has a number of pixels assigned to each bit.
False
(T or F) The sonographer CANNOT change, directly or indirectly, the duty factor of an ultrasound machine.
False
(T or F) There have NOT been biological effects from ultrasound found in the laboratory.
False
(T or F) With normal incidence the angle is 180°
False
(T or F) With the right angle incidence, reflections are always generated at a boundary if the propagation speeds of the media are different.
False
(T or F) a mirror image artifacts can appear along side of the true anatomy.
False
The manufacturer increases the number of lines per frame. As a result, which of the following may have to be decreased? Frequency (T or F) Frame rate (T or F) Sector angle (T or F) Imaging depth (T or F) Power output (T or F)
False, true, true, true, false
What are the units of longitudinal resolution?
Feet
While scanning in a water tank, what location in a sound beam has the highest intensity?
Focal point
What is the location of a minimum cross-sectional area of the ultrasound being called?
Focus
Lateral resolution can be improved by _________.
Focusing
What is the significance of grayscale variation in the spectrum of a pulsed wave Doppler display?
It represents the number of red blood cells creating the reflection
Which of the following will result in the greatest number of shades of gray in a digital image display?
Large pixels with many bits per pixel
What can pulsed Doppler measure that continuous wave cannot?
Location
Particles move back and forth in the same direction (aLONG) as the wave is known as a _______ wave.
Longitudinal wave
Sound waves are:
Longitudinal, mechanical
Which of the following will result in the highest mechanical index? ______ frequency and high signal amplitude
Low
Under what circumstance is cavitation most likely to occur? _____ frequency and high signal amplitude
Low frequency and high signal amplitude
From a safety standpoint, which one of the following methods is best?
Low transmit output and high receiver gain
How is range ambiguity artifact eliminated?
Lower the PRF
Images on videotape are stored using ________.
Magnetism
A single element transducer is focused by the _____.
Manufacturer
_________ _______ is associated with cavitation.
Mechanical index (MI)
Which of the following has a propagation speed closest to soft tissue?
Muscle
With normal incidence, what factors affect refraction of ultrasound?
None of the above
Refraction requires both:
Oblique Incidence & Different speeds
Anything other than 90°; not at right angles is known as ______ ______.
Oblique incidence
Which of the following is not a beam steering technique for a mechanical scanhead?
Phased beam
You enter a hospital room to perform an ultrasound exam. Which of the following should you do first?
Politely check the patients wrist band for identification
Which of is associated with power mode Doppler? ______ temporal resolution & ______ artifact
Poor; Flash artifact
The rate that sound travels through a medium also called velocity or speed is known as _____ ____.
Population speed
______ is proportional to the amplitude squared.
Power
Concentration of force within an area is known as __________.
Pressure
3 acoustic variables: ______, _______, ______
Pressure, density, and distance
Impedance is the ______ of ______ and ______.
Product, propagation speed, density
In soft tissue: Distance traveled = _______ x Round trip time
Propagation speed
_________ ______ and the _______ ______ have the greatest influence on temporal resolution.
Propagation speed and the imaging depth
The actual time that ultrasound machine is creating a pulse is known as _____ ______.
Pulse duration
The time from the beginning of a pulse until it's end is known as ________.
Pulse duration
________ Doppler Has the greatest output intensity.
Pulsed
Coded excitation originates in the _______.
Pulser
Where does coded excitation originate? in the ______
Pulser
It's a waves amplitude is doubled, what happens to the power?
Quadrupled
______ resolution is determined by the spatial pulse length.
Radial or axial resolution
Which of the following choices best describes in ideal epidemiologic bioeffects study?
Randomized and prospective
_______ ______ artifact is created by an object that is located deeper then image.
Range ambiguity
Which of the following is determined by the source and the medium?
Range resolution
__________ are areas of DECREASED pressure and density.
Rarefactions
The dB is defined as the ________ of two intensities
Ratio
A red blood cell is a ______ ______.
Rayleigh scatterer
Which of the following tissues is most likely to create Rayleigh scattering?
Red blood cells
Which of the following choices determines the signal amplitude in the transducer of an ultrasound system?
Reflected intensity of the sound beam
Which one of the following sets of properties of a test Phantom is most relevant when assessing depth calibration accuracy?
Reflector spacing and propagation speed
Snell's law describes physics of __________.
Refraction
The angle of incidence of an being is perpendicular to an interface.The two media have the same propagation speeds. What process cannot occur?
Refraction
If the wires in an AIUM test object do not appear in the same place as on the display, what is a miss?
Registration accuracy
______ is used to alter the appearance of lowly reflective objects.
Reject
_________ is the elimination of voltages that do not exceed a certain level.
Reject
If the frequency of ultrasound is increased from 0.77 MHz to 1.54 MHz, what happens to the propagation speed?
Remains the same
Multiple reflections that are equally space are known as ________.
Reverberations
With the presence of ______ we see more boundaries then there are reflecting surfaces.
Reverberations
Which of these intensities is the smallest?
SATA
What component of the ultrasound unit contains the memory bank?
Scan converter
Pre-processing occurs when the patient is ______.
Scanned
Lung attenuates sound by _________.
Scattering
________ is a redirection of ultrasound in many directions as a result of a rough boundary between two media.
Scattering
What are the three components of attenuation?
Scattering, reflection, absorption
The more bits per pixel the more _____________.
Shades of gray
Which type of artifact appears most commonly with highly reflective objects?
Shadowing
Higher frequency sound has ________ wavelengths.
Shorter
You are performing a quality assurance study on an ultrasound system using a tissue equivalent phantom. You make an adjustment using a knob on the system console that changes the appearance of reflector brightness from fully bright to barely visible. What are you a evaluating?
System sensitivity
In which of these biologic tissues will sound waves propagate most quickly? Tendon, blood, lung, fat, amniotic Fluid
Tendon
In which way is in annular phased array transducer different than a linear phased array transducer?
The annular is steered mechanically
Assuming a constant frequency, what happens if the diameter of an unfocused circular transducer is increased?
The beam width in the near field is increased
What is the meaning of a thermal index = 3?
Tissue temperature may rise 3°C
Particles move in a perpendicular direction (Right angles for 90°) to the direction of the wave is known as a _________ wave.
Transverse wave
(T or F) Doppler shifts always occur if the source and Observer are in motion relative to each other and the angle between the motion and the sound beam is NOT 90°
True
(T or F) Gray scale can be changed by the sonographer.
True
(T or F) Shadowing may result from high amounts of reflection of US energy.
True
A system which was working well now does not display clear images in the far field. This may be a problem with the: Transducer (T or F) Receiver (T or F) Monitor (T or F) Scan converter (T or F)
True, true, true, true
All of the following are true EXCEPT:
Two waves with identical frequencies must interfere constructively
Sound must travel through a medium. Sound cannot travel through a _________.
Vacuum
What information does Doppler shift provide?
Velocity
A sound beam strikes obliquely does reflection or transmission occur?
WE DON'T KNOW
Power of sound has units of _______.
Watts
Unit of intensity =
Watts/cm²
The length for distance of a single cycle is known as the __________.
Wavelength
________ is the distance covered by one cycle.
Wavelength
Average speed of sound through tendons =
about 1,850 m/s
What is not the responsibility of the sonographer?
adjust converter matrix
Greatest attenuating media to lowest attenuating media:
air > bone & lung > soft tissue > water
Put tissue types in order from slowest to fastest:
air > lung > fat > soft tissue (blood, too) > tendon > bone
Which of these boundaries will create the strongest reflection? air-lung air-soft tissue air-blood soft tissue-blood
air-soft tissue
Sound is traveling from medium 1 to medium 2. Propagation speeds of M-1 and M-2 are 1,600 m/s and 1,500 m/s, respectively. There is normal incidence. angle of incidence = _____ __ _______
angle of reflection
Volume has units of ____.
cm³
Best describes the mechanistic approach to the study of bioeffects?
cause-effect
As a rule transducers should be disinfected using ________ or ________.
cidex or gluteradehyde
Circumferences may be measured in a unit of:
cm
What may be a unit of amplitude?
cm
Put in decreasing order:
deca - deci - centi - micro
Compression is used to ______ the range of amplitudes.
decrease
What happens to venous return to the heart during expiration?
decreased
In a real-time scanner, the ______ ___ ______ determines the maximum frame rate.
depth of view
Which of these factors has the greatest influence on pulse repetition period?
display depth
Speed =
distance/time
It's a reflector is moved twice as far away from the transducer, how this affect the time-of-flight of a sound pulse?
doubles
What increases patient exposure?
exam time
Best describes the empirical approach to the study of bioeffects?
exposure-response
Rayleigh scattering is related to __________.
frequency⁴
If the frequency of an ultrasound wave is doubled, what happens to the period?
halved
If the frequency of ultrasound is increased from 0.77 MHz to 1.54 MHz, what happens to the wavelength?
halved
Traveling through the same medium, if the frequency is doubled, the wavelength is ______.
halved
Impedance equation:
impedance (rayls OR "Z") = density(kg/m³) x propagation speed (m/s)
The Doppler Shift is a measure of the difference between ________ and _______ frequency.
incident and reflected frequency
Lower frequency sound has ________ wavelengths.
longer
Which has the correct units for Freq - Speed - Intens - Atten
mHz - m/sec - W/cm² - dB
Fresnel zone is the _____ zone.
near
In an air-tissue interface, near ____% of the ultrasound is reflected.
near 100%
The angle between an ultrasound pulse and the boundary between two media is 56°. This is called: ________ incidence
oblique
In soft tissue, attenuation coefficient is:
one-half of the transducers frequency 0.5 dB/cm/MHz
The range equation relates distance from reflector to ______ and _____.
time-of-flight and Propagation speed
Traveling through the same medium, if the frequency is doubled, the propagation speed is ______.
unchanged
What are the units of intensity?
watts/cm squared
the PZT is 1/2 the ______ thick
wavelength
Wavelength equation:
wavelength (mm) = Propagation speed (mm/µs) ÷ frequency (MHz) OR L or λ = C/F OR wavelength (mm) = 1.54 mm/us ÷ frequency (MHz)
