SPI REVIEW QUESTIONS: Transducers
During an exam, you change from a 5MHz transducer to a 3MHz transducer. What happens to the period of the waves produced from the new transducer? A. increases B. decreases C. remains constant D. unable to determine
A increases
Which of the following transducers would be preferred for breast imaging? A. 10MHz linear array B. 10MHz curved array C. 8MHz sector array D. 8MHz mechanical
A. 10MHz linear array
If the fundamental frequency of a transducer is 3 MHz, what is the second harmonic frequency for this transducer? A. 6MHz B. 4.5Mhz C. 1.5MHz D. 12MHz
A. 6MHz
. The wider the element diameter, the A. longer the near zone. B. greater the beam intensity. C. greater the probe frequency. D. greater the beam divergence in the far field.
A. Longer the near zone.
Which of the following correctly describes how a linear array transducer produces a trapezoid field of view? A. PE elements are stimulated by timed voltage spikes produced in a convex pattern B. PE elements are stimulated by timed voltage spikes produced first on the right and moving to the left side of the array C. PE elements are stimulated by timed voltage spikes produced in a concave pattern D. PE elements are stimulated by timed voltage spikes produced first on the left and moving to the right side of the array
A. PE elements are stimulated by times voltage spikes produced in a convex pattern
Which of the following is correct regarding endocavity probes? A. They most commonly incorporate a curved array of elements that are electronically steered to create an extended field of view. B. They should be cleaned and soaked in a high level disinfectant at least once a day. C. One of the main disadvantages of the tightly curved elements of the endocavity probe is decreased spatial resolution. D. Endocavity probes offer improved lateral resolution at greater depths.
A. They most commonly incorporate a curved array of elements that are electronically steered to create an extended field of view.
How can you adjust the elevation focus to a more superficial location in a 1D array transducer? A. use a stand off pad B. scan the breast from a lateral approach C. there is no way to adjust the elevation focus in a 1D array D. change the short axis focus setting on the console
A. Use a stand off pad
All of the following can be used for backing material in PW probe, except: A. air B. putty C. cork D. epoxy
A. air
Which of the following statements correctly describes annular arrays? A. An annular array can electronically focus the beam. B. An annular array can use phasing to electronically steer the beam. C. Annular arrays provide the lowest slice thickness resolution. D. Annular arrays usually contain 30 or more circular elements.
A. an annular array can electronically focus the beam
Which of the following transducers is capable of electronic beam steering? A. curvilinear phased array B. curvilinear sequential array C. linear sequential array D. mechanical
A. curvlinear phased array
If you change from transducer with a 40mm crystal thickness to one with a 20mm crystal thickness, the frequency of the sound produced will: A. double B. increase by 1/2 C. increase by a factor of 4 D. decrease by 1/4
A. double
Which of the following system functions allows the linear transducer to offer a trapezoidal field of view? A. electronic steering B. apodization C. electronic focusing D. mechanical focusing
A. electronic steering
Which of the following describes a vector array transducer? A. Has a sector shaped field of view with a flat top B. Uses mechanical steering C. Used for breast imaging and extremity vascular exams D. Uses only mechanical focusing
A. has a sector shaped field of view with a flat top
Which of the following describes a Multi-dimensional array? A. has thousands of elements arranged in a matrix pattern B. offers increased slice thickness and improved spatial resolution C. has less than 100 elements that can be fired simultaneously D. has less than 100 elements that can be fired sequentially
A. has thousands of elements arranged in a matrix pattern
Increasing the angle of electronic steering causes ______________ production of lobe artifact. A. increased B. decreased C. no change D. limited
A. increased
Which of the following can be done to reduce the beam divergence? A. switch to a higher frequency transducer B. deactivate dynamic focusing C. remove an acoustic lens in front of the PE element D. switch to a lower frequency transducer
A. switch to a higher frequency transducer
Which of the following is true regarding annular arrays and linear arrays? A. Annular arrays must be mechanically steered, linear arrays use electronic steering. B. Annular arrays and linear arrays can be electronically steered. C. Annular arrays have multiple elements, linear arrays have a single element. D. Annular arrays can be electronically steered, linear arrays must be mechanically steered.
A.Annular arrays must be mechanically steered, linear arrays use electronic steering
___________________ determines the acoustic power of the transducer. A. The magnitude of the voltage spike B. The frequency of the transducer C. The diameter of the matching layer D. The size of the PE element
A: The magnitude of the voltage spike.
Mirrors and lenses can be used to ________________. A. mechanically focus the US beam B. increase the PRF of the transducer C. improve sound transmission into the body D. electronically focus the US beam
A: mechanically focus the ultrasound beam
The matching layer for a transducer is usually made of plastic and is approximately ________________ . A. 1/2 of the probe wavelength in thickness B. 1/4 of the probe wavelength in thickness C. 1/4 of the probe spatial pulse length in thickness D. 4 times the probe wavelength in diameter
B. 1/4 of the probe wavelength in thickness
18. Diagnostic ultrasound is described as frequencies greater than: A. 1MHz B. 2MHz C. 2.5MHz D. 3MHz
B. 2MHz
Which of the following transducers will produce the highest frequency sound waves? A. 6mm element thickness, 2mm/μs propagation speed of the element B. 2mm element thickness, 6mm/μs propagation speed of the element C. 6mm element thickness, 6mm/μs propagation speed of the element D. 2mm element thickness, 2mm/μs propagation speed of the element
B. 2mm element thickness, 6mm/ms propagation speed of the element Thinner elements with higher propagation speeds produce the highest frequency waves
Which of the following is NOT correct regarding phased array transducers? A. A sector phased array has a fan shaped field of view. B. All phased array transducers are focused electronically. C. All phased array transducers are steered electronically. D. A linear phased array can produce a trapezoidal image.
B. All phased array transducers are steered electronically
Which of the following is true regarding continuous wave transducer structure and function? A. CW probes usually require a double thickness of matching layer compared to a PW probe of the same frequency. B. CW probes usually have no backing material except a pocket of air posterior to the element. C. Higher frequency CW probes have the highest duty factor % of all CW probes. D. CW probes have a single PE element.
B. CW probes have no backing material except a pocket of air posterior to the element
15. Which two factors determine the focal depth of a transducer? A. element thickness and diameter B. element diameter and frequency C. element thickness and frequency D. propagation speed and element diameter
B. Element diameter and frequency
Which of the following statements is true regarding the advantage of a mechanical annular probe over the mechanical single element probe? A. The array of elements allows for electronic steering which is not possible with a single element. B. The array of elements allows for electronic focusing which is not possible with a single element. C. The array of elements allows for mechanical steering which is not possible with a single element. D. The single element probe will have higher temporal resolution than the annular array.
B. The array of elements allows for electronic focusing which is not possible with a single element.
What type of transducer has a cylindrical beam profile? A. curved array B. annular array C. linear array D. phased array
B. annular array
You switch from a 5MHz curved probe to a 2.5MHz sector probe to image deeper in the abdomen. How is the attenuation rate affected by the change to the new probe? A. decreases by 25% B. decreases by 50% C. Doubles D. increases by 4 times
B. decreases by 50%
The crystal in the ultrasound transducer converts: A. electrical energy into heat energy B. electrical energy into mechanical energy C. mechanical energy into heat energy D. all of the above
B. electrical energy into mechanical energy
____________________ used to form the sector shaped field of view for a phased array transducer. A. The curved arrangement of the elements are B. Electronic steering is C. An acoustic lens is D. Electronic focusing is
B. electronic steering
The frequency of the transducer depends primarily on the _______________. A. element diameter B. element thickness C. thickness of the matching layer D. thickness of the backing layer
B. element thickness
Which of the following correctly describes how the elements of a sequential linear transducer are excited? A. varies with exam preset selection on the system B. in a specific order that does not change C. elements are excited left to right with a 0.01ms between each voltage spike D. varies with transmitted frequency of the transducer
B. in a specific order the does not change
All of the following transducers can be focused at multiple depths, except: A. annular phased B. mechanical single element C. curvilinear phased D. linear phased
B. mechanical single element
The matching layer is usually made of _____________. A. quartz B. plastic C. air D. cork
B. plastic
What shape is the image display from a sequential linear transducer? A. flat top triangle B. rectangle C. wedge shaped with curved top D. trapezoidal
B. rectangle
Which of the following transducers provides the best spatial resolution of the cardiac structures? A. curved sequential array B. transesophageal array C. vector array D. phased sector array
B. transesophageal array
Which of the following can be used to eliminate the dead zone on the image? A. place multiple focal zones at the top of the image B. use a standoff pad C. decrease the depth to the lowest setting and turn of harmonic imaging D. not possible to eliminate the dead zone from an image
B. use a standoff pad
Transducers can be electronically focused by: A. adding an acoustic lens to the face of the transducer B. varying timing of the release of the pulses C. using a convex shaped PE element D. using a concave shaped element
B. varying timing of the release of the pulses
Which of the following transducer frequencies can be used for imaging or therapeutic purposes? A. 15MHz B. 3MHz C. 1MHz D. 5MHz
B: 3MHz therapeutic transducers range between 0.7-3MHz
Which of the following applies to therapeutic ultrasound transducers? A. backing material at least 2X thickness of that used in imaging transducers B. narrow bandwidth C. frequencies >15MHz used due to the increased potential for focused cavitation D. low Q factor
B: Narrow Bandwidth
Which of the following describes a purpose for applying acoustic gel to the face of the transducer? A. To increase the amount of reflection that occurs within the first 2cm of tissue B. To reduce the difference in impedance between the matching layer and the skin C. To increase the amount of refraction that occurs within the first 2cm of tissue D. To reduce the beam intensity just before the sound beam enters the patient
B: to reduce the difference in impedance between the matching layer and the skin
Which type of transducer would be used to evaluate a palpable lump in the neck? A. 12MHz sector phased array B. 3MHz curvilinear sequential array C. 12MHz linear phased array D. 12MHz curvilinear phased array
C. 12MHz linear phased array
Which of the following transducers would be most useful for imaging deeper structures? A. 5 MHz long focus B. 3 MHz short focus C. 3 MHz long focus D. 5 MHz short focus
C. 3 MHz long focus
Which of the following transducers will produce the lowest frequency sound waves? A. 6mm element thickness, 6mm/μs propagation speed of the element B. 2mm element thickness, 2mm/μs propagation speed of the element C. 6mm element thickness, 2mm/μs propagation speed of the element D. 2mm element thickness, 6mm/μs propagation speed of the element
C. 6mm element thickness, 2mm/ms propagation speed of the element. thicker elements with slower propagation speeds produce the lowest frequency waves
You switch from a 5MHz curved probe to a 2.5MHz sector probe to image deeper in the abdomen. How is the wavelength affected by the change to the new probe? A. has no effect when changing from curved to sector transducer B. decreases by 50% C. Doubles D. increases by a factor of 4
C. Doubles
As frequency increases, the axial resolution will A. depends on how the PE elements are arranged B. be degraded C. improve D. remain unchanged
C. Improve
Lowering the transducer frequency will: A. improve temporal resolution B. increase sector size C. increase the mechanical index D. decrease the propagation speed
C. Increase the mechanical index
All of the following are advantages of harmonic imaging, except: A. decreased lobe artifact B. increased signal to noise ratio C. increased beam penetration D. decreased reverberation artifact
C. Increased beam penetration
Which of the following correctly describes an annular array? A. produces a trapezoid shaped field of view B. improved temporal resolution is a primary advantage of annular arrays C. offers excellent lateral resolution D. produces a sector shaped field of view with a flat top
C. Offers excellent lateral resolution
As the area of the beam increases, _________________________________________________. A. the intensity of the beam decreases B. the frequency increases C. the intensity of the beam increases D. the wavelength increases
C. The intensity of the beam increases
104. Which transducer component improves elevational resolution? A. pulser B. damping layer C. acoustic lens D. matching layer
C. acoustic lens
As transducer frequency increases: A. lateral resolution will improve but axial resolution will be degraded B. lateral resolution will be degraded bu axial resolution will improve C. axial and lateral resolution will improve D. axial and lateral resolution will be degraded
C. axial and lateral resolution will improve
Which of the following exams would benefit from an exam performed with a multidimensional array? A. carotid exam with a high grade stenosis B. breast biopsy to localize the lesion in several planes C. cardiac exam to evaluate left atrial and ventricular volume D. abdominal exam on an obese patient
C. cardiac exam to evaluate left arterial and ventricular volume
22. Spatial compounding requires a transducer that can perform: A. harmonic imaging B. dynamic frequency tuning C. electronic steering D. electronic focusing
C. electronic steering
Which of the following factors affect the focal length of the transducer? A. element thickness and diameter B. element frequency and PRF C. element diameter and frequency D. element diameter, frequency and thickness
C. element diameter and frequency
Quality factor = _________________ ______ _____________________ A. dynamic range / bandwidth B. bandwidth X frequency C. frequency / bandwidth
C. frequency/bandwidth
All of the following occur with the implementation of backing material, except A. lower Q-factor B. reduced duty factor C. improved sensitivity D. shorter pulses
C. improved sensitivity
As the propagation speed of the crystal increases, the frequency of the transducer: A. decreases B. does not change C. increases D. depends on the thickness and diameter of the crystal
C. increases frequency of the transducer and propagation speed are directly related
Which of the following statements is true regarding damage to the matching layer of the transducer? A. The use of more acoustic gel is required to increase the distance between the probe and the skin surface. B. It causes an increase in the intensity of the beam and increased exposure to the patient. C. It causes an increased risk of electrical shock to the patient. D. It is normal for it to develop small holes after extended use
C. it is an increased risk of electrical shock to the patient
66. A linear transducer providing a trapezoidal image demonstrates degraded ___________ resolution in the far field of the image. A. elevational B. axial C. lateral D. contrast
C. lateral
Which transducer component improves lateral resolution? A. matching layer B. backing material C. pulser D. thicker PE element
C. pulser
Which of the following types of PE crystals are usually used for high frequency transducers (>18MHz) used in musculoskeletal exams ? A. rochelle salt B. barium sulfate C. quartz D. lead titanate
C. quartz quartz is commonly used in high frequency construction
Which of the following describes the primary advantage of a 1.5D array over a 1D array? A. the 1.5D array can produce a trapezoid field of view while the 1D array can only produce a rectangular field of view B. the 1.5D array eliminates the need for a stand-off pad for superficial imaging C. the 1.5D array allows for variable elevation focus while the 1D array has a fixed elevation focus D. the 1.5D array allows for 3D imaging while the 1D array does not
C. the 1.5D array allows for variable elevation focus while the 1D array has a fixed elevation focus
Transducers can be electronically focused by: A. adding an acoustic lens to the face of the transducer B. using a convex shaped PE element C. varying timing of the release of the pulses D. using a concave shaped element
C. varying timin of the release of the pulses
Which type of transducer has the smallest field of view in the near field? A. curvilinear B. vector C. sector D. linear
C: Sector
A curved array transducer is preferred over a sector array transducer of the same frequency for fetal and abdominal imaging because: A. it offers increased penetration B. it produces a lower intensity beam C. it has a wider near field D. it offers less beam divergence
C: it has a wider near field
Which of the following statements is false regarding transducer selection? A. A high frequency transducer has improved axial resolution compared to a lower frequency transducer. B. A high frequency transducer has improved lateral resolution compared to a lower frequency transducer. C. A high frequency transducer has less far field beam divergence than a lower frequency transducer. D. A high frequency transducer has greater depth penetration than a lower frequency transducer.
D. A high frequency transducer has greater depth penetration than a lower frequency transducer.
Which statement regarding high frequency transducers is correct? A. Higher frequency transducers always have low signal to noise ratio B. Higher frequency transducers provide improved image resolution because the sound travels faster through the tissues to provide a more accurate display. C. Harmonic imaging should never be used on transducers over 12MHz D. A multi-Hz transducer operates at multiple frequencies and offers a broad bandwidth.
D. A multi-Hz transducer operates at multiple frequencies and offers a broad bandwidth
Which of the following transducers will provide the deepest natural focus? A. Low frequency, large diameter B. Low frequency, small diameter C. High frequency, small diameter D. High frequency, large diameter
D. High frequency, large diameter these will have the deepest natural focus
All of the following correctly describe the damping material in the transducer, except: A. it decreases spatial pulse length B. it reduces the "ringing" of the crystal C. it improves longitudinal resolution D. it improves lateral resolution
D. It improves lateral resolution
What is the proper method used to assess the size of the dead zone? A. Trace the volume of the portion of the image that demonstrates reverberation at the top of the screen B. Measure the width of the area of reverberation at the top of the screen C. Trace the area of the portion of the image that demonstrates reverberation at the top of the screen D. Measure from the top of the image to the depth that uniform tissue is identified
D. Measure from the top of the image to the depth that uniform tissue is identified
Linear phased arrays utilize what type of focusing? A. mechanical only B. electronic only C. elevational only D. mechanical and electronic
D. Mechanical and electronic
. When scanning the thyroid, you change from a 5MHz probe to a 10MHz probe. Which of the following statements is false? A. The spatial resolution will improve with the 10MHz transducer. B. The 2D imaging depth settings are much more limited in the 10MHz transducer. C. There will be increased attenuation with decreased penetration with the 10MHz probe. D. The reflected waves will be more quickly received and processed by the 10MHz probe.
D. The reflected waves will be more quickly recieved and processed by the 10MHz probe
The linear transducer you are using has 7-5MHz printed on the side of the housing. What probe characteristic is this? A. dynamic range B. duty factor C. system sensitivity D. bandwidth
D. bandwidth
All of the following are coupling agents or mediums typically used for US exams, except: A. KY jelly B. ultrasonic gel C. water D. gastrografin
D. gastrografin gastrografin is only used for radiology purposes
Some US transducer arrays allow you to increase the focusing along the width of the beam. What effect will this change have on the image? A. decreased beam attenuation B. improved contrast resolution C. degraded temporal resolution D. improved elevational resolution
D. improved elevational resolution
The wider the element diameter, the A. shorter the near zone. B. greater the probe frequency. C. greater the beam divergence in the far field. D. lower the beam intensity.
D. lower the beam intensity
The coupling gel used for ultrasound exams provides the same function as what transducer component? A. backing layer B. damping layer C. PE element D. matching layer
D. matching layer
What type of probe is preferred for cardiac imaging? A. Phased Curved B. Curved Sequential C. Linear Sequential D. Phased Sector
D. phased sector
Which of the following transducers uses a beam former? A. sequential curved linear array B. mechanical transducer C. sequential linear array D. sector phased array
D. sector phased array
Materials used for the matching layer of a transducer must have an impedance between impedance levels of the __________________________ A. acoustic gel and air B. skin and acoustic gel C. PE element and damping layer D. skin and PE element
D. skin and PE element
8. A ___________MHz transducer will have the thinnest element. A. 3 B. 5 C. 7 D. 12
D: 12 higher frequencies will have the thinnest elements
How do elements relate to the beam?
Elements that are THINNER produce a higher frequency beam. Element (width) diameter does not effect the frequency of the sound produced.
frequency equation
F=prop speed/2x(thickness of element)
Frame Rate Formula
FR= PRF/lines per frame
What do multidimensional arrays do?
Multidimensional arrays can produce 3D/4D images, which is the preferred method for volume assessment.
How is quality factor related to frequency?
The higher the frequency, the higher the Q factor and narrower the bandwidth.
1.5D transducer
automatically change the slice thickness focal zone when the focal zone is changed by the transducer because of the multiple transmit focal zones
What are the advantages of a multi-dimensional transducer?
improves elevational thickness by reducing slice thickness
How are frequency and element thickness related?
inversely
Elevation resolution/Slice thickness
resolution in the third dimension of the beam
What is divergence?
spreading of the beam that occurs in the far zone.
sensitivity
the ability of the machine to display low-level or weak echoes
Spatial Resolution
the ability of the system to distinguish between closely spaced objects; refers to axial, lateral, contrast, and elevational resolution
Range resolution
the ability to determine how far away a reflector is so it can be displayed on the screen; without range resolution there is depth ambiguity
temporal resolution
the ability to display structure in real time, AKA frame rate
phased array
the transducer that uses phasing, or small time differences, to steer and focus the beam
mechanical scanheads
transducers with a motor for steering the beam