Comprehensive and Detailed Explanation From Exact Extract:
Using multiple focal zones improves lateral resolution but requires additional time for each focal zone acquisition, which reduces frame rate and therefore degrades temporal resolution.
According to sonography instrumentation reference:
“Multiple focal zones improve lateral resolution but at the expense of temporal resolution due to longer acquisition time for each frame.”
Therefore, the correct answer is D: Temporal.
68
Which setting is the most likely cause of the artifact displayed in this image?
A close-up of a ultrasound
Description automatically generated
A. Color gain set too low
B. Color gain set too high
C. Velocity scale set too high
D. Velocity scale set too low
Answer: D
Comprehensive and Detailed Explanation From Exact Extract:
The image shows color aliasing, where the colors abruptly change within the vessel indicating wrap-around of Doppler shifts. This happens when the velocity scale (PRF) is set too low, causing velocities exceeding the Nyquist limit to alias.
According to sonography instrumentation reference:
“Aliasing occurs in color Doppler when the flow velocities exceed the Nyquist limit, commonly due to a low velocity scale (PRF).”
Therefore, the correct answer is D: Velocity scale set too low.
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