Instrumentation Flashcards
🎗What is B-Mode?
Brightness mode principle, offers a gray scale image
🎗What is the optimal transducer frequency for breast imaging?
10.0 to 18.0 MHz for superior axial and lateral resolution (detail) while maintaining penetration to chest wall
🎗A _____ transducer (wide frequency range) is optimal.
broadband
🎗What’s the trade-off between high and low frequency probes?
High frequency has superior detail but low penetration.
Low frequency has superior penetration but less detail.
🎗What probe design is optimal for breast imaging?
Linear array
1) rectangular image
2) direct contact perpendicular to chest wall
3) accurate measurements by avoiding beam divergence artifact
4) accurately guides interventional procedures
Why is the linear array optimal?
When might a curved array be used?
If a mass is too large to fit on a linear image (larger field of view, but lost resolution).
What’s the difference between the 1-D Linear and 1.5-D Matrix Array?
1-D has a single element across the short axis of the probe and a fixed elevation focus.
1.5-D has multiple elements across the short axis and can focus in both directions (better detail)
An imaging depth between __ and __ cm should be adequate.
3 and 6 cm
🎗This adjusts the brightness of each echo.
Gain (the amount of amplification applied)
🎗This controls the level of brightness of all echoes appearing on an image
Overall Gain
🎗This allows for the brightness to be controlled at varying depths throughout the image.
TGC (Time Gain Compensation)
This is the state-of-the-art feature that optimizes overall gain and TGC.
Auto Gain Optimization (‘the magic button’)
What’s the ALARA Principle?
Output power should be set ‘As Low As Reasonably Achievable’.
What happens when the power is decreased?
The image gets darker.
Can the brightness be increased without increasing the power?
Yes, by increasing the gain
Does increasing the gain have any effect on patient exposure to ultrasound energy?
No
🎗When should the sonographer decrease the Output Power?
If your image is too bright, decrease the output power. If your image is too dark, increase the receiver gain.
Multiple focal zones will yield the best ____ throughout the entire image at the expense of a ________.
best resolution; slower frame rate
Multiple focal zones are recommended, but if a single focus is used, set it at the ____.
depth of the area of interest
Define elevation plane focus
the focus in the short axis or elevation plane (short side) of an electronic transducer
🎗What’s the elevation plane focus in a 10 MHz probe? (conventional linear array)
1.5 cm
What kind of gray scale and dynamic range is used for breast imaging?
BROAD gray scale and HIGH dynamic range - provides a lot of gray shades to show subtle detail.
Acoustic enhancement
generally associated with a cyst or benign lesion
Shadowing
generally associated with a solid/malignant lesion
🎗Reverberation
artifactual linear echoes parallel to a strong interface. May have a distinct ‘stepladder ‘ or ‘Venetian blind’ appearance
Side or Grating Lobe
secondary sound sources off the main sound beam that place artifactual eches within a cyst
Slice (Section) Thickness
unwanted echoes from the thickness of the sound beam in the elevation plane that place artifacts within a cyst
🎗Nipple Shadowing
shadowing in the subareolar region may be eliminated by angling the transducer posterior to the nipple or by using the ‘rolled nipple’ technique
🎗Volume Averaging
decreases contrast resolution and spatial resolution (both axial and lateral). Places unwanted echoes in cysts.
What are four reasons artifacts or unwanted echoes may show up in cysts?
reverb, side/grating lobe, slice/section thickness, and volume averaging
Power doppler is [MORE or LESS] sensitive to low-velocity flow.
More
Doppler is most helpful in distinguishing… (3 things)
1) cystic vs solid
2) inflamed vs non-inflamed
3) complicated cyst vs complex cyst or intraductal papilloma
Doppler will NOT tell you the difference between… (1 thing)
benign vs malignant
What kind of transducer pressure should be used with doppler breast scanning?
Minimal. Small vessels are easily compressed.
🎗Doppler technique: In order to optimize, the sonographer should establish a technique for ___ velocity flow states.
Low
Techniques for low-velocity flow states include: (4 things)
1) Low velocity scale (5-6 cm/s)
2) Low filter setting
3) Optimal color gain setting
4) Increased PRF for high-velocity flow velocities
Spatial compounding is
used to combine multiple scan lines acquired from different directions (angles).
Advantages of spatial compounding
sharper margins and reduced speckle
Disadvantages of spatial compounding
reduces enhancement and shadowing, appears blurry
Technique wherein the system ignores echoes from the transmitted frequency and captures echoes from the received frequency
Harmonic Imaging
1) Improves detail resolution
2) Improves contrast resolution
3) Reduces artifact chose in breast cysts
Advantages of harmonic imaging (3)
Disdavantage of harmonic imaging (1)
May lose detail in the far field
Diagnostic method that evaluates the elastic properties of tissue
elastography
Which is more stiff - malignant tumors or benign?
malignant
What uses mechanical compression to deform the tissues and measure the reaction?
Strain elastography
Is the strain elastography color map qualitative or quantitative?
qualitative
Soft tissues will be [BLUE or RED] with strain elastography.
Blue
Stiff tissues will be [BLUE or RED] with strain elastography.
Red
What is the measurement used in strain elastography to represent not only the stiffness of the lesion, but the stiffness of the surrounding tissue involved in the cancer?
E/B Ratio
What do the E and B stand for in E/B Ratio?
Elastogram, B-Mode
What indicates a desmoplastic reaction (cancer invading the surrounding tissue)?
E/B Ratio of greater than 1 = BIRADS 5
What is a common artifact of strain elastography that appears in breast cysts?
The ‘Tri-Laminar’ or ‘BGR’ artifact - all three colors are displayed within the cyst.
