Comprehensive and Detailed Explanation From Exact Extract:

The primary purpose of compression is to reduce the dynamic range of received echoes, making the image more visually interpretable by adjusting contrast without losing diagnostic information.

According to sonography instrumentation reference:

“Compression reduces the dynamic range of the signal amplitudes to fit within the display range of the monitor while preserving important differences in tissue echogenicity.”

Therefore, the correct answer is D: Reduce the dynamic range.

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Comprehensive and Detailed Explanation From Exact Extract:

Each additional focal zone requires extra transmissions per scan line, which slows down frame acquisition, thereby reducing the frame rate.

Principles and Instrumentation state:

"Increasing the number of focal zones lowers frame rate because multiple pulses are needed per scan line for each focal depth."

Increasing PRF (B) allows faster data acquisition.

Decreasing depth (C) shortens round-trip time, increasing frame rate.

Decreasing sector width (D) reduces scan lines, increasing frame rate.

Comprehensive and Detailed Explanation From Exact Extract:

Ideal imaging transducers have broad bandwidths (allowing multiple frequencies for better axial resolution and flexibility) and a low quality factor (which indicates efficient damping, leading to short pulses and better image quality).

According to sonography instrumentation reference:

“Imaging transducers operate with broad bandwidth and low quality factor to achieve short pulse duration and optimal axial resolution.”

Therefore, the correct answer is B: Broad bandwidth; low quality factor.

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The color Doppler image shows an artifact where high-velocity blood flow exceeds the Nyquist limit, resulting in color wrap-around or aliasing. This artifact is visualized as a mosaic pattern of colors that abruptly change, indicating that the velocity exceeds the color Doppler scale's maximum. Aliasing occurs when the sampling rate (pulse repetition frequency) is insufficient to accurately capture the high velocities, causing the display to cycle back to lower velocities.

Persistence is a technique used in ultrasound imaging that averages individual frames together to improve the overall image quality. This process helps to reduce noise and improve the signal-to-noise ratio, leading to clearer and more stable images. By averaging multiple frames, transient artifacts are minimized, and the continuity of structures is better visualized. Persistence is particularly useful in imaging static or slow-moving structures.References:

ARDMS Sonography Principles and Instrumentation guidelines

"Ultrasound Physics and Technology: How, Why and When" by M. Evans, C. Archer, and K. Weston

Lateral resolution refers to the ability of the ultrasound system to distinguish two structures that are side by side, perpendicular to the direction of the sound beam. This resolution is primarily improved by reducing the beamwidth. A narrower beamwidth allows for better differentiation between adjacent structures, enhancing the lateral resolution. Higher frequency transducers can also help achieve a narrower beamwidth, but beamwidth is the primary factor.

Comprehensive and Detailed Explanation From Exact Extract:

Continuous wave (CW) Doppler utilizes two separate crystals: one constantly transmitting and one constantly receiving. This setup allows CW Doppler to measure very high velocities without aliasing, but at the cost of losing range specificity (no depth resolution).

According to sonography instrumentation reference:

“Continuous wave Doppler uses two separate elements for continuous transmission and reception of sound waves, allowing for detection of very high velocities but without depth specificity.”

Therefore, the correct answer is D: Dedicated transmit and receive crysta

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What artifact is indicated by the arrows in the image below?

An ultrasound image of a fetus Description automatically generated

A. Ring down

B. Grating lobe

C. Enhancement

D. Refraction

Answer: A

Comprehensive and Detailed Explanation From Exact Extract:

The image shows a bright, continuous, vertical band extending from a gas-containing structure (seen at the top). This is characteristic of ring down artifact, which occurs when multiple small gas bubbles resonate and create continuous echoes below the structure.

According to sonography instrumentation reference:

“Ring down artifact results from resonance of gas bubbles, producing a continuous series of echoes distal to the source. It appears as a bright, vertical band that does not fade with depth.”

Therefore, the correct answer is A: Ring down.

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