Comprehensive and Detailed Explanation From Exact Extract:
Persistence is a post-processing technique that averages multiple consecutive frames to reduce random noise and smooth the displayed image. It helps enhance image quality by stabilizing slow-moving or stationary structures while sacrificing some temporal resolution.
As per official sonography Principles and Instrumentation guidelines:
"Persistence is a frame averaging technique that reduces speckle and temporal noise, improving image smoothness by combining data from successive frames."
Elastography measures tissue stiffness.
Panoramic imaging extends the field of view.
Fusion imaging combines ultrasound with other imaging modalities.
Therefore, the correct answer is C: Persistence.
QUESTION NO10
Which change would allow low velocities to be displayed in this spectral Doppler image?
A close-up of a ultrasound
Description automatically generated
A. Decrease compression
B. Increase sample volume size
C. Increase transmitted frequency
D. Decrease wall filter
Answer: D
Comprehensive and Detailed Explanation From Exact Extract:
In the spectral Doppler display shown, the wall filter setting determines the lower limit of velocity signals that are displayed. A high wall filter removes low-velocity signals (such as end-diastolic flow or slow venous flow), while a lower wall filter allows both high and low velocities to be visualized.
According to the official Principles and Instrumentation documents:
"The wall filter eliminates low-frequency Doppler shifts, which correspond to low-velocity blood flow or motion artifacts. Decreasing the wall filter allows display of low-velocity flow components that may otherwise be filtered out."
Decreasing compression (A) adjusts dynamic range but does not influence velocity detection.
Increasing sample volume size (B) affects spatial resolution and signal amplitude but not velocity thresholds.
Increasing transmitted frequency (C) may improve sensitivity but does not directly control the display of low velocities.
Therefore, the correct answer is D: Decrease wall filter.
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