SPI Practice Exam 2 Flashcards
Which type of bioeffects research uses data acquired from patients or subjects that have been exposed to ultrasound to describe the bioeffects that were experienced?
A: subjective approach
B: empirical approach
C: mechanistic approach
D: qualitative approach
B
Empirical research is based on observed and measured phenomena and derives knowledge from actual experience rather than from theory or belief.
Qualitative research involves collecting and analyzing non-numerical data (e.g., text, video, or audio) to understand concepts, opinions, or experiences.
What system setting should be adjusted to better visualize possible stone in the ureter posterior to the bladder?
A: reduce the rejection settings
B: turn off spatial compounding
C: increase the dynamic range
D: turn up the overall gain
B
If the time to produce each frame is 0.01 sec, what is the frame rate?
A: 10Hz
B: 10kHz
C: 100Hz
D: 100kHz
Which if the following characteristics of an LCD monitor determines the spatial resolution of the 2D image?
A: number of pixels
B: size of the patient
C: number of voxels
D: speed of the digital to analog converter
A
The number of pixels on the display determines the spatial resolution of the image displayed.
*Note: voxel - In 3D computer graphics, a voxel represents a value on a regular grid in three-dimensional space. As with pixels in a 2D bitmap, voxels themselves do not typically have their position explicitly encoded with their values
*The artifact that is produced when the incident beam hits a curved surface and produces an acoustic shadow is referred to as:
A: multi-path artifact
B: comet tail
C: mirror imaging
D: defocusing
D
Edge shadowing is also termed defocusing or refractive shadowing and refers to shadowing caused by the beam hitting the curved edge of a round object
*Which of the following describes the difference between side lobes and grating lobes?
- grating lobes are seen with arrays and side lobes are seen with single element probes
- grating lobes are corrected by apodization and subdicing is used to correct side lobes
- grating lobes are corrected by subdicing and apodization is used to correct side lobes
- grating lobes are seen with curved arrays and side lobes are seen with linear arrays
A
*Grating lobes are weak off axis portions of the beam that degrade lateral resolution. grating lobes are seen with arrays and side lobes are seen with single element probes
_________ resolution is defined as the ability of an ultrasound system to differentiate structures on an image based on variations in the brightness of the echo/pixel
- elevational
- axial
- lateral
- contrast
4
Contrast resolution refers to the ability to distinguish between different echo amplitudes of adjacent structures. Contrast resolution may be enhanced at various stages in the imaging process, these include compression, image memory, and the use of contrast agents.
*Note:
Axial resolution: the ability of an ultrasound system to distinguish two structures that lie parallel to the ultrasound beam as separate and distinct
Lateral resolution: the ability of an ultrasound system to distinguish two structures that lie perpendicular to the ultrasound beam as separate and distinct
Which of the following is a responsibility of a sonographer when assisting with an intravascular ultrasound?
- to operate the u/s machine controls from outside of the sterile field
- to advance the u/s catheter during the procedure
- to send the u/s catheter for sterilization after the procedure
- to perform preliminary IVUS images before the star of the angioplasty procedure
1
*note: u/s catheter CANNOT be sterilized, it is disposable.
This procedure is performed by the physician while the sonographer assists from outside the sterile field
*Increasing the edge enhancement setting will:
- improve contrast resolution
- increase image contrast
- amplify reflections on the edges of the image
- produce a smoother image
2
*edge enhancement: spatial high pass filter used to emphasize changes in brightness across the image to make boundaries of vessel walls and organs more prominent.
*What is the function used with color Doppler analysis to assess the data from multiple sampling sites and produce a display representing mean flow velocities?
- autocorrelation
- Bernoulli equation
- Quadrature phase detection
- Fast fourier transformer
1
- Autocorrelation is used with color Doppler analysis to assess the data from multiple sampling sites and and procedure a display representing mean flow velocities
- FFT is used to process the PW Doppler signal
- Quadrature phase detection is a nearly obsolete
*Frame rates can be improved by the use of what signal processing technique?
- autocorrelation
- parallel processing
- FFT
- demodulation
2
*parallel processing of multiple lines of signals at the same time will increase frame rates
What artifact is demonstrated on the image?
- mirror image
- edge shadowing
- side lobes
- range ambiguity
4
- Edge shadowing appears as linear posterior shadowing originating at a round edge
- Side lobes are weak, off axis lobes that degrade lateral resolution
- mirror image artifacts are created as sound reflects off of a very strong reflector
- range ambiguity artifact occurs in superficial structures and is caused by the presence of multiple highly reflective surfaces *artifacts can be minimized by increasing the distance of the structure from the face of probe
Transmit delay or receive focusing improves ______ resolution.
- temporal
- axial
- contrast
- lateral
- lateral
Azimuthal and angular resolution refer to lateral resolution. lateral resolution is improved with a thinner beam. Focusing forms a thinner beam in the focal zone, therefore focusing improves the lateral resolution.
*Which of the following will improve slice thickness resolution?
- decreasing damping levels
- adding an external focusing lens
- decreasing transmitted frequency
- decrease rejection
- adding an external focusing lens
Mechanical focusing decreases the slice thickness of the image which improves elevational or slice thickness resolution.
The matching layer for a transducer is usually made of plastic and is approximately ______
- 4 times the probe wavelength in diameter
- ¼ of the probe wavelength in thickness
- ¼ of the probe spatial pulse length in thickness
- ½ of the probe wavelength in thickness
2.
The matching layer for a transducer is usually made of plastic and is approximately ¼ pf the probe wavelength in thickness
Which of the following is a function of the pulser used to increase the signal to noise ratio?
- dynamic receiving focusing
- temporal compounding
- mechanical index
- coded excitation
coded excitation
coded excitation is a process performed in the pulser. it is used to create long sound pulses that contain a wide bandwidth for increased power and penetration. It produces increased signal to noise ratio and improves image quality by improving penetration and axial, spatial and contrast resolution.
*There is no known adverse biological effect in vivo using focused ultrasound transducer at intensities below ______
- 100 mW/cm2 SATA
- 1000 mW/cm2
- 100 mW2/cm SPTA
- 1 W/cm2 SPTA
4
*tricky question
UNFOCUSED transducer: 100 mW/cm2 SPTA
FOCUSED transducer: 1 W/cm2 SPTA
*If media 1 has an impedance of 65 rayls and media 2 also has an impedance of 65 rayls, what percentage of the beam will be reflected at their interface?
- 100%
- 50%
- 0%
- unable to determine with information given
0%
If the acoustic impedance of the two media are identical, no reflection will occur at their border
*Virtual beam forming significantly improves all types of resolution compared to pulse echo imaging, except:
- lateral resolution
- contrast resolution
- axial resolution
- temporal resolution
axial resolution
*virtual beam forming has many advantages over traditional pulse echo imaging. It offers significant improvement of lateral, contrast, and temporal resolution. the rapid image processing is also a key advantage
What is the most common Doppler artifact?
- blooming
- ghosting
- clutter
- aliasing
aliasing
Contrast resolution is calculated by dividing the dynamic range by the:
- number of shades of grey
- number of reflections received
- number of bits in the memory
- number of pixels in the memory
number of shades of grey
*contrast resolution is defined as decibels per shade.
Contrast resolution = dynamic range/number of shades
If the dynamic range is 40dB and there are 20 shades of grey, the contrast resolution is 2sB/shade
Which of the following settings should be increased when evaluating venous flow on Doppler?
- PRF
- output power
- color priority
- wall filter
color priority
*Color-write priority is an adjustable setting of color Doppler duplex ultrasound and determines whether a particular pixel on the image displays color or grayscale B-mode information at the moment.
Color-write priority is rarely changed directly during routine ultrasound imaging, even though it can significantly improve flow detection in low caliber vessels. While in large vessels there is a well-defined, mostly anechoic lumen easily written over with color information, the visible lumen of small vessels not only has a more discrete lumen, but it is also less likely to be anechoic due to e.g. reverberation artifacts. Adjusting the color-write priority (usually displayed as a horizontal bar on the grayscale spectrum) can facilitate the display of these vessels. This can be particularly useful e.g. in the interrogation of testicular blood flow 1
Which of the following is inversely related to the Doppler shift?
- speed of the red blood cells
- number of red blood cells
- speed of the sound in tissue
- sine of the angle between the flow and the detector
speed of the sound in tissue
Doppler shift = 2vfcosθ/c
*If the speed of sound in tisue increases, the Doppler shift decreases
Which setting should be lowered to the minimum level when beginning to evaluate the patient using the orbital window?
- Doppler gain
- Wall filter
- Output Power
- Velocity scale
output power
*The intensity of the sound beam passed though the eye should be set to the lowest level possible
Focusing of the transmitted and received beam occurs in the:
- image processor
- beam former
- image former
- signal processor
beam former
*The beam former generates the voltages applied to the transducer. It determines the PRF, frequency and intensity of the beam.
Scanning, focusing, and apodization of the transmitted beam are also functions of the beam former.
The best obtainable angle of insonation for vascular evaluation that is most commonly used to provide Doppler shift information is ____ degree.
60
*Note
The best angle of insonation to produce the most accurate Doppler shift information is 0 degree.
The best OBTAINABLE angle of insonation of a blood vessel that is most commonly used to provide Doppler shift information is 60 degree
What is the cause of the vertical acoustic shadow seen on both images?
- patient motion
- element damage
- electrical interference
- air in the trachea
electrical interference
*Note the vertical black stripe that originates at the face of the transducer. It is located in the same place on the image as you can scan different anatomy
*In a 4 bit memory, the binary number 1110 indicates which of the following numbers related to location of the display of the echo on the screen?
- 10
- 12
- 14
- 24
14
The binary system works the same way as decimal. The only difference is that instead of multiplying the digit by a power of 10, we multiply it by a power of 2.
Which of the following is an advantage of the new Capacitive Micromachined Ultrasonic Transducers (CMUT) compared to traditional transducer arrays?
- produces a lower intensity beam that traditional transducer of the same frequency
- a narrower bandwidth and improved detail resolution
- a coupling gel i not needed for sound transmission
- a wider bandwidth and improved detail resolution
4
CMUTs are the transducers where the energy transduction is due to change in capacitance. CMUTs are constructed on silicon using micromachining techniques. A cavity is formed in a silicon substrate, and a thin layer suspended on the top of the cavity serves as a membrane on which a metallized layer acts an electrode, together with the silicon substrate which serves as a bottom electrode.
*The advantage over PZT elements include the ability to integrate with electrical circuits, a wider bandwidth, improved detail resolution, allowing 3D imaging using 2D array, and improved cost effectiveness
*Which of the following lists all of the components of the US system?
- transducer, receiver, memory, pulser, display
- transducer, memory, display, scan converter
- transducer, receiver, scan converter, display
- pulser, transducer, memory, display
1
*an ultrasound system contains 5 main components: pulser, transducer, receiver, memory, and display
Activation of B-color is used to improve:
- elevational resolution
- spatial resolution
- contrast resolution
- temporal resolution
contrast resolution
*B-color = colorize (talking about applying different color instead of grey such as chrome, blue etc…)
Use your cursor to measure the end diastolic velocity of the third waveform. Use your mouse to position the cursor and click to set your answer.
*Note the Doppler measurement on the image. What other Doppler measurement should be taken to calculate the resistive index?
- EDV
- PDV
- PSV
- ESV
***Bandpass filtering is a function performed in the:
***
- peak systolic velocity
- peak diastolic velocity
- peak systolic velocity
- end diastolic velocity
What is the twinkle artifact?
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beam former
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C
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axial resolution
*VBF offers significant improvement of lateral, contrast, and temporal resolution
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Lateral resolution is improved at the focal zone and in the near field compared to the far field
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C
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C
