Ch 17: Harmonics & Contrast Agents Flashcards
This is the creation of an image from sound reflections at twice the frequency of the transmitted sound.
harmonic imaging
The transmitted frequency is called the __ frequency.
fundamental
The __ frequency is twice the transmitted frequency.
harmonic
Harmonic frequency sound waves arise from __ behavior.
nonlinear
This is the image created by processing reflections that are twice the fundamental frequency.
harmonic image
This is the image created by processing reflections that have the same frequency as the transmitted sound.
fundamental image
What two forms of harmonics are important in diagnostic sonography?
- tissue harmonics
2. contrast harmonics
This kind of behavior is proportional and symmetrical.
linear
This kind of behavior is irregular and disproportionate.
nonlinear
T/F? Tissue harmonics happens during transmission.
true
The __ of the harmonic wave grows as sound travels in tissue.
strength
Tissue harmonic signals do not exist at __ depths.
extremely superficial
The use of harmonics __ the signal-to-noise ratio.
increases
T/F? The relationship between sound beam strength and harmonic creation is linear.
FALSE, nonlinear
Beams that are most likely to create harmonics are least likely to create __.
artifacts.
T/F? Tissue harmonics are primarily created along the beam’s side lobes.
FALSE, along the beam’s main axis
This is an imaging technique specifically designed to utilize harmonic reflections while eliminating distorted fundamental reflections.
pulse inversion harmonics
With pulse inversion harmonics, a __ pulse is followed by a __ pulse.
typical, inverted
In pulse inversion harmonics, the typical and inverted pulse reflections are combined in the…
receiver.