Which type of structure is best visualized with low persistence?
Answer(s): D
Low persistence is best used for visualizing dynamic structures. Persistence is a setting that controls the averaging of successive frames to reduce noise and improve image quality. While high persistence can be beneficial for imaging static structures by providing a smoother image, it can blur or smear moving structures, making it difficult to visualize motion accurately. Low persistence settings allow for better temporal resolution and are therefore ideal for observing dynamic or moving structures such as the heart or blood flow.
ARDMS Sonography Principles and Instrumentation (SPI) Exam Study Guide"Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
What is the relationship between overall gain and image brightness?
Answer(s): A
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.
Which settings will lead to the highest temporal resolution?
The settings that lead to the highest temporal resolution are those that reduce the amount of information that the ultrasound system needs to process, allowing for a higher frame rate. A smaller sector width and shallower scan depth reduce the area that needs to be imaged, enabling faster data acquisition. Turning off color Doppler further reduces processing demands, as the system no longer needs to compute and display color flow information. Therefore, a 45-degree sector width, 4 cm scan depth, and color Doppler off will provide the highest temporal resolution.
Which parameters determine the propagation speed of sound in a medium?
The propagation speed of sound in a medium is determined by the medium's elasticity and density. Elasticity refers to the ability of the medium to return to its original shape after deformation, while density is the mass per unit volume of the medium. The speed of sound increases with higher elasticity and decreases with higher density. This relationship is described by the equation = v=E, where v is the propagation speed, E is the elasticity (or modulus of elasticity), and is the density.
Which target group in this image of a tissue-mimicking phantom is used for gray-scale evaluation?
Answer(s): C
Gray-scale evaluation in a tissue-mimicking phantom involves assessing the uniformity and accuracy of the gray-scale representation of the tissues.Option C typically contains structures designed to test the machine's ability to accurately depict varying levels of echogenicity, which is essential for proper gray-scale evaluation.This area will have a range of echo intensities that help in determining the contrast resolution and the ability of the system to distinguish between different tissue types based on their gray-scale values.
ARDMS Sonography Principles and Instrumentation guidelines on tissue-mimicking phantoms and image quality evaluation.
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