ARDMS SPI Attenuation, Reflection, and Refraction 4

Question 1

Acoustic shadowing distal to a gallstone is primarily due to:

Accepted Answer

High attenuation and reflection by the calcified stone

Answer

Gallstones strongly reflect and absorb sound, leaving a shadow of reduced echo amplitude posterior to the stone.

Question 2

Which property of a medium directly determines whether refraction will occur at an oblique interface?

Accepted Answer

Propagation speed

Answer

Refraction depends on differing propagation speeds in adjacent media, not on their impedances.

Question 3

The average propagation speed of sound in soft tissue used by ultrasound systems is:

Accepted Answer

1540 m/s

Answer

Ultrasound machines assume a propagation speed of 1540 m/s in soft tissue for depth calculations.

Question 4

Non-specular (diffuse) reflectors differ from specular reflectors in that they:

Accepted Answer

Scatter sound in many directions regardless of beam angle

Answer

Non-specular (diffuse) reflectors have irregular or small surfaces that scatter sound in all directions, making them angle-independent.

Question 5

Which factor does NOT directly affect the intensity reflection coefficient at a tissue interface?

Accepted Answer

Transducer frequency

Answer

At normal incidence, the reflection coefficient depends only on the two media's acoustic impedances, not on frequency.

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test