Free ARDMS SPI Practice Exam with Questions & Answers | Set: 6

Color Doppler imaging is most effective when the angle between the ultrasound beam and the flow of blood is small.

At an angle of 88 degrees, the flow of blood is nearly perpendicular to the ultrasound beam.

When the angle is close to 90 degrees, the Doppler shift (frequency change) approaches zero, resulting in little to no color being visualized on the Doppler image.

Thus, to obtain a color signal, the angle should be optimized to be as close to 0 degrees as possible, with 60 degrees being the practical limit for accurate Doppler measurements.References:

ARDMS Sonography Principles and Instrumentation guidelines on Doppler angle and its effect on Doppler imaging.

Comprehensive and Detailed Explanation From Exact Extract:

Temporal resolution reflects how quickly frames are updated (frame rate). Reducing the number of scan lines per frame (low line density) decreases acquisition time, thus increasing frame rate and improving temporal resolution.

According to sonography instrumentation reference:

“Lower line density allows for faster frame rates, improving temporal resolution at the expense of spatial resolution.”

Therefore, the correct answer is D: Low line density.

Power Doppler, unlike color Doppler, is less angle dependent because it detects the strength of the Doppler signal rather than the velocity of the blood flow. This means it is more sensitive to detecting low-velocity flow and flow in smaller vessels, regardless of the angle between the ultrasound beam and the flow direction. Color Doppler provides information on flow direction and velocity but is highly dependent on the angle of insonation, making it less reliable when the angle is suboptimal.

ARDMS Sonography Principles and Instrumentation guidelines

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

Overall gain controls the amplification of all the received ultrasound signals uniformly. This adjustment affects the brightness of the entire image by increasing or decreasing the amplification of the echoes returning from all depths. It is a primary control for adjusting image brightness. The overall gain should be set to an appropriate level to ensure that the ultrasound image is neither too bright (over-gained) nor too dark (under-gained), allowing for optimal visualization of the anatomical structures.

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

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:

The proper care and reprocessing of ultrasound transducers follow a strict hierarchy of steps. The first step is always physical cleaning, which involves removing visible debris, gel, and contaminants from the transducer surface. This must be done prior to any disinfection or sterilization process because organic material can inhibit the effectiveness of these subsequent steps.

According to sonography Principles and Instrumentation documentation:

"Cleaning is the first and essential step in reprocessing ultrasound probes. It removes gel, blood, and other organic material. Disinfection or sterilization should never be performed before cleaning, as residual debris reduces their effectiveness."

Therefore, the correct answer is C: Clean.

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