SPI Exam Dumps - Sonography Principles and Instrumentation

When utilizing multiple transmit focal zones, the ultrasound system must perform multiple transmissions at each focal depth. This process requires more time for data acquisition, which in turn decreases the frame rate. A lower frame rate directly impacts temporal resolution, which is the ability to accurately depict moving structures over time. Thus, using multiple focal zones improves lateral resolution but degrades temporal resolution.

Comprehensive and Detailed Explanation From Exact Extract:

Spatial compounding uses multiple scan angles to create an image. By combining information from different angles, it can reduce shadowing artifacts caused by highly attenuating structures.

According to sonography instrumentation reference:

“Spatial compounding reduces artifacts such as posterior shadowing by averaging images acquired from multiple insonation angles.”

Therefore, the correct answer is A: Increasing spatial compounding.

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Overall gain in ultrasound refers to the amplification of all the received echo signals. Increasing the overall gain amplifies the signals, making the entire image brighter. Conversely, decreasing the overall gain reduces the signal amplification, resulting in a darker image. Overall gain adjustment affects the entire image uniformly, unlike time gain compensation (TGC), which adjusts the gain at different depths independently.

References

ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide

"Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau

A wall filter in Doppler ultrasound is designed to remove low-frequency signals that are often caused by tissue motion, vessel wall movement, or other forms of motion artifact. These low-frequency signals can clutter the Doppler spectrum, making it difficult to accurately interpret blood flow velocities. By filtering out these unwanted low-frequency signals, the wall filter helps to enhance the clarity of the Doppler signal, allowing for more accurate measurements of blood flow velocities.

American Registry for Diagnostic Medical Sonography (ARDMS). Sonography Principles and Instrumentation (SPI) Examination Review Guide.

To avoid exceeding the Nyquist limit and prevent aliasing in Doppler ultrasound, the pulse repetition frequency (PRF) should be increased. The Nyquist limit is half of the PRF, so by increasing the PRF, the Nyquist limit is raised, allowing the system to accurately measure higher velocities without encountering aliasing artifacts.

ARDMS Sonography Principles and Instrumentation guidelines

Zwiebel, W. J., & Pellerito, J. S. (2017).Introduction to Vascular Ultrasonography. Elsevier.