How can the spectral Doppler mirroring seen in this image be eliminated?
Answer(s): B
Spectral Doppler mirroring, also known as crosstalk, occurs when the Doppler signal appears on both sides of the baseline. This can be caused by excessively high Doppler gain, which amplifies the signal and creates artificial mirror images. Decreasing the Doppler gain reduces the signal amplitude, thereby minimizing the mirroring artifact.
ARDMS Sonography Principles and Instrumentation guidelinesHoskins, P. R., Thrush, A., Martin, K., & Whittingham, T. A. (2010). Diagnostic Ultrasound: Physics and Equipment.
What is the primary interaction that occurs when sound waves encounter a smooth, flat surface?
When sound waves encounter a smooth, flat surface, the primary interaction is reflection. This means the sound waves bounce back towards the transducer, producing echoes that are used to create the ultrasound image. Reflection is most effective when the surface is smooth and perpendicular to the sound beam, allowing for the maximum return of sound waves to the transducer.
ARDMS Sonography Principles and Instrumentation guidelinesZagzebski, J. A. (1996). Essentials of Ultrasound Physics.
Which artifact results from decreased attenuation?
Enhancement is an artifact that results from decreased attenuation. When an ultrasound wave travels through a medium with lower attenuation compared to surrounding tissues, it loses less energy. Consequently, the structures located deeper than the low-attenuation medium appear brighter on the ultrasound image. This artifact is commonly observed behind fluid-filled structures, such as cysts or the urinary bladder, where the sound waves encounter minimal resistance and thus less attenuation.
ARDMS Sonography Principles and Instrumentation guidelines"Diagnostic Ultrasound: Principles and Instruments" by Frederick W. Kremkau
What does changing the displayed depth control directly affect?
Answer(s): A
Changing the displayed depth control directly affects the pulse repetition frequency (PRF). When the depth setting is increased, the ultrasound system needs more time to send and receive echoes from deeper structures, resulting in a lower PRF. Conversely, decreasing the depth allows for a higher PRF since the time required for the sound waves to travel to and from the structures is shorter. PRF is crucial for determining the maximum detectable velocity in Doppler ultrasound without aliasing.
ARDMS Sonography Principles and Instrumentation guidelines"Understanding Ultrasound Physics" by Sidney K. Edelman
What is the term for an ultrasound system's ability to display low-level echoes?
Answer(s): C
Sensitivity is the term for an ultrasound system's ability to display low-level echoes. It refers to the system's capacity to detect and accurately display weak echoes returning from tissues. High sensitivity allows the sonographer to visualize structures that produce faint echoes, such as small or low-contrast lesions. This parameter is critical for ensuring that subtle pathological changes are not missed during imaging.
ARDMS Sonography Principles and Instrumentation guidelines"Sonography: Principles and Instruments" by Joan P. Baker and Marveen Craig
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