RVT Ultrasound Physics and Instrumentation 3

Question 1

Acoustic shadowing distal to a calcified vessel wall is caused by:

Accepted Answer

High reflection and absorption at the calcified interface preventing sound transmission

Answer

Calcifications have high acoustic impedance and absorb/reflect most incident sound energy, leaving little to penetrate further and creating a shadow behind the calcification.

Question 2

A mirror image artifact in Doppler ultrasound refers to:

Accepted Answer

A duplicate spectral waveform appearing on the opposite side of the baseline

Answer

Doppler mirror image artifact creates a duplicate spectral waveform below the baseline that mimics reversed flow; it results from excessive gain or strong specular reflectors redirecting sound.

Question 3

Harmonic imaging improves image quality primarily by:

Accepted Answer

Using second-harmonic frequencies generated within tissue to reduce near-field clutter and side-lobe artifacts

Answer

Tissue harmonic imaging receives echoes at twice the transmitted (fundamental) frequency; because harmonics build up within tissue rather than at the transducer surface, near-field artifact and clutter are greatly reduced.

Question 4

Lateral resolution in ultrasound imaging is best at the:

Accepted Answer

Focal zone of the transducer

Answer

Lateral resolution (ability to separate two side-by-side structures) is optimal at the focal zone where the beam is narrowest, and degrades in both the near and far fields as the beam diverges.

Question 5

The ALARA principle in diagnostic ultrasound stands for:

Accepted Answer

As Low As Reasonably Achievable

Answer

ALARA (As Low As Reasonably Achievable) directs sonographers to use the lowest acoustic output necessary to obtain diagnostic images, minimizing potential bioeffects.

(RVT) Registered Vascular Technologist Practice Test

(RVT) Registered Vascular Technologist Practice Test

RVT Ultrasound Physics and Instrumentation 3