ARDMS SPI Attenuation, Reflection, and Refraction 3

Question 1

What artifact is produced when refraction causes the beam to miss its intended target?

Accepted Answer

Lateral displacement artifact

Answer

Refraction can displace the apparent position of a structure laterally, creating a lateral displacement artifact.

Question 2

At normal incidence, what determines the fraction of sound intensity reflected at an interface?

Accepted Answer

The difference in acoustic impedance between the two media

Answer

The reflection coefficient at normal incidence depends solely on the acoustic impedances of the two media.

Question 3

Which of the following interfaces reflects nearly 100% of incident sound energy?

Accepted Answer

Soft tissue–air interface

Answer

The acoustic impedance mismatch between soft tissue and air is extreme, causing nearly total reflection and no transmission.

Question 4

The angle of refraction is related to the angle of incidence by:

Accepted Answer

Snell's law

Answer

Snell's law (sin θ₁/c₁ = sin θ₂/c₂) governs the relationship between the angle of incidence and angle of refraction.

Question 5

Acoustic impedance (Z) is calculated as:

Accepted Answer

Density × propagation speed

Answer

Acoustic impedance Z = ρ × c, where ρ is the tissue density and c is the propagation speed.

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test