ARDMS SPI Acoustic Waves and Properties 3

Question 1

Which tissue type has the highest acoustic propagation speed?

Accepted Answer

Bone

Answer

Bone has the highest stiffness among listed tissues, giving it the greatest propagation speed (~3500 m/s).

Question 2

Specular reflection occurs when sound strikes a boundary that is:

Accepted Answer

Large and smooth relative to the wavelength

Answer

Specular reflectors are large, flat, smooth surfaces that reflect sound at an angle equal to the incident angle, like a mirror.

Question 3

Attenuation of ultrasound in soft tissue is approximately:

Accepted Answer

0.5 dB/cm/MHz

Answer

The standard approximation for attenuation in soft tissue is 0.5 dB/cm/MHz, used clinically for TGC calculations.

Question 4

Scattering of ultrasound is most likely to occur when the reflecting structure is:

Accepted Answer

Similar in size or smaller than the wavelength

Answer

Non-specular (diffuse) scattering occurs when reflectors are small relative to wavelength, producing omnidirectional echoes used in gray-scale imaging.

Question 5

When sound passes from a medium with low acoustic impedance to one with high acoustic impedance, the reflected wave will have:

Accepted Answer

A phase shift of 180°

Answer

Reflection at an interface where impedance increases causes a 180° phase reversal (pressure inversion) of the reflected wave.

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI Acoustic Waves and Properties 3