Comprehensive and Detailed Explanation From Exact Extract:
Cross talk (spectral mirror artifact) appears as a duplication of the spectral waveform above and below the baseline. One primary cause is excessive Doppler gain, which amplifies weak signals and noise symmetrically. Reducing gain minimizes this artifact.
Principles and Instrumentation state:
"Cross talk in spectral Doppler may result from high gain settings. Lowering the gain can reduce or eliminate this artifact."
PRF adjustments affect aliasing, not cross talk.
Baseline shifts affect waveform positioning.
Wall filter affects low-frequency signals but not cross talk.
Therefore, the correct answer is A: By decreasing the Doppler gain.
QUESTION NO28
Which artifact is demonstrated by the arrow in this image?
A close-up of an ultrasound
Description automatically generated
A. Mirroring
B. Noise
C. Shadowing
D. Enhancement
Answer: C
Comprehensive and Detailed Explanation From Exact Extract:
The image shows an area of signal dropout directly deep to the strongly reflecting structure (likely a vessel wall or calcification), indicated by the arrow. This is a classic example of shadowing artifact.
According to sonography Principles and Instrumentation:
"Shadowing occurs when a highly attenuating or reflective structure blocks the ultrasound beam, resulting in absence of signal distal to the object."
Mirroring (A) produces duplicated structures.
Noise (B) appears as random speckles.
Enhancement (D) produces increased echogenicity distal to an anechoic structure.
Therefore, the correct answer is C: Shadowing.
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