Ultrasound Physics Flashcards
If TGC is increased in the far field of the image, what changes are seen?
Deep tissues become brighter
Regarding ultrasound transducer technology…
High frequency yield best resolution but lose penetration
By placing the transducer more perpendicular to a lesion, what feature is more likely to be appreciated on sonography?
Pseudocapsule
Doppler is not reliable in distinguishing benign from malignant.
True
A checkerboard appearance or arrangement of piezoelectric crystals on the face of a transducer describes a…
Matrix array probe
For breast imaging, why is a broad gray scale map or high dynamic range optimal?
Many shades of gray will demonstrate subtle tissue differences
Benefits of spacial compounding in breast ultrasound?
Sharper margins
Smoother, more realistic image of the tissue
Better tissue differentiation
Which of the linear transducers is most likely to have an elevation plane focus of 1.5cm?
10MHz
What kind of artifacts cause unwanted echoes within a cyst?
Reverberation, slice thickness artifact, and volume averaging
If TGC is decreases in the near field of the image, what changes are seen?
Superficial tissues become darker
When establishing an optimal depth for each patient, what landmark should be used?
Chest wall
Attenuation of sound through breast tissue is due to?
Reflection
Absorption
Scattering
Gray scale technique for breast ultrasound should be set so mid-level gray echoes represent
Fat
If the image looks to dark, what is the first adjustment you should make?
Increase gain
Ultrasound operated by
B mode or brightness mode
Reverberation is an artifact commonly seen as
Multiple, parallel echoes or venetian blind effect
If the output power is decreased, what changes are seen on the image?
Entire image becomes darker
If a linear array transducer emittes multiple sound beams at different angles best represents
Spatial compounding
The benefit of a matrix array transducer for breast imaging is
Improved electronic focusing in the elevation plane
Shadowing is caused by
Strongly reflecting or attenuating structures
What is the speed of sound in silicone relative to fat
Slower
Which artifacts may be seen as multiple, parallel lines in the anterior portion of a cyst?
Reverberation
Techniques to improve artifact in the bear field are
Increase transducer pressure, increase frequency, add focal zones in the near field
What transducer is most likely to have an elevation plane focus of 3-4 cm
5MHz
Which shade of gray is brighter on an ultrasound image?
Moderately hyperechoic
The brightness or echo amplitude of the breast tissue on ultrasound may be controlled by
Gain, TGC, and acoustic power
If the image is to bright what adjustment should be made first?
Decrease the output power
Advantages of Harmonic ultrasound imaging?
Artifact reduction
Improved contrast
Improved detail
Real-time is ultrasound’s ability to
See things in motion in the body
By applying firm transducer pressure while scanning, the sonographer may improve
Resolution (detail)
Sound transmission
Penetration
TGC stands for
Time gain compensation
Useful artifacts in breast imaging and are termed “diagnostic markers”
Shadowing and enhancement
What does mildly hyperechoic mean?
Slightly brighter than medium gray
Optimizing doppler technique for breast imaging usually includes
Low velocity
Low filter
Sensitive gain setting
Under which scanning conditions is increased transducer pressure not helpful
Color Doppler
Technically, how can artificial echoes in the near field be removed from an image?
Add focal zones
If the overall gain is increased, what changes are seen on the image?
The entire image becomes brighter
If a 5MHz signal is transmitted but a 10MHz signal is received, this is what type of imaging?
Harmonic
What frame rate is considered real time?
15 frames per second or greater
The terms mildly, moderately, and markedly can be applied to further describe the echogenicity of a structure. What does markedly hypoechoic mean?
Significantly dark shade of gray
How can a sonographer reduce shadowing from Cooper’s ligaments?
Change the angle of the transducer or apply a little more pressure
When establishing correct gray scale and gain settings for so ographic breast imaging, all structures should be compared to the mid-level echogenicity of?
Fat
Which shade of gray is darker on an ultrasound?
Markedly hypoechoic
Which shade of gray is darker on an ultrasound?
Markedly hypoechoic
Multi-focus or variable focusing capabilities is optimal in breast imaging because it provides?
Best resolution the full depth of the image
Non useful artifacts in breast imaging
Reverberation, slice thickness, side love
While scanning through silicone implants, the ultrasound system places the chest wall deeper than the true chest wall depth. This artifact is known as?
Speed error
The reduction of intensity of a sound wave as it travels through a material describes
Attenuation
Under what conditions would a sonographer consider using a 7MHz transducer for breast imaging
Large breasted females
If a tissue weakly reflects ultrasound, it will have what appearance on the image?
Dark or dark gray or hypoechoic
ALARA
As low as reasonably achievable
A sector image is
Pie-shaped
Two tissues are equal or similar in gray shade appearance
Isoechoic
When does the sonographer know an optimal TGC setting is achieved?
A uniform gray scale pattern is seen from skin to chest wall
If a tissue strongly reflects ultrasound, it will have what appearance on the image?
Bright or white or hyperechoic
Ideal transducer frequency for breast imaging is
10-18 MHz
Which is the optimal flow setting for color doppler evaluation of a solid breast mass?
Low velocity scale
The ability to see detail on an ultrasound image including both lateral and axial resolution is called
Spatial resolution
