UTC Ultrasound Physics & Instrumentation 3

Question 1

Acoustic shadowing artifact in ultrasound appears as a dark region posterior to a structure because:

Accepted Answer

A highly reflective or strongly attenuating structure blocks sound transmission beyond it

Answer

Sound waves accelerate after passing through the structure

Answer

Sound waves bounce between two parallel surfaces within the structure

Answer

The transducer frequency is too high for the imaging depth

Question 2

Posterior acoustic enhancement occurs posterior to which type of structure?

Accepted Answer

Fluid-filled structures such as simple cysts

Answer

Calcified structures such as gallstones

Answer

Gas-filled structures such as bowel

Answer

Dense bone cortex

Question 3

The ALARA principle as applied to diagnostic ultrasound means:

Accepted Answer

As Low As Reasonably Achievable

Answer

Always Lower Acoustic Resolution Achievable

Answer

Accurate Lateral And Range Assessment

Answer

Automatic Level And Range Adjustment

Question 4

Reverberation artifact in ultrasound is characterized by which appearance?

Accepted Answer

Multiple equally spaced parallel hyperechoic lines anterior to a highly reflective surface

Answer

Increased brightness posterior to a fluid-filled structure

Answer

Distortion and bowing of structures near a curved reflector

Answer

Complete loss of echoes posterior to a calcified focus

Question 5

Cavitation as a bioeffect of ultrasound specifically involves:

Accepted Answer

Formation and oscillation of microbubbles in tissue due to acoustic pressure variations

Answer

Tissue heating caused by absorbed acoustic energy

Answer

Direct mechanical stress fracturing of cellular membranes

Answer

Reduction in propagation speed causing image distortion

Question 6

The mechanical index (MI) displayed on an ultrasound scanner primarily indicates risk for which bioeffect?

Accepted Answer

Cavitation

Answer

Thermal heating of tissue

Answer

Image resolution degradation

Answer

Transducer crystal fatigue

Question 7

Mirror image artifact in ultrasound is best described as:

Accepted Answer

A duplicate of a real structure appearing on the opposite side of a strong curved reflector such as the diaphragm

Answer

Multiple equally spaced echoes caused by reverberation between parallel surfaces

Answer

Enhanced brightness posterior to a cystic structure

Answer

Dark shadowing posterior to a calcification