ARDMS SPI Image Formation and Processing 3

Question 1

Which type of resolution describes the ability to distinguish two closely spaced reflectors located side by side perpendicular to the beam axis?

Accepted Answer

Lateral resolution

Answer

Lateral resolution refers to the minimum separation between two targets in the plane perpendicular to the beam and is determined by beam width at a given depth.

Question 2

Axial resolution in ultrasound is primarily determined by:

Accepted Answer

Spatial pulse length

Answer

Axial resolution equals half the spatial pulse length; shorter pulses (higher frequency, fewer cycles) yield finer axial resolution.

Question 3

Elevational (slice thickness) resolution is most directly controlled by:

Accepted Answer

The fixed focusing of the transducer in the elevation plane

Answer

Elevational resolution depends on the fixed mechanical lens focus in the elevation dimension, which cannot be dynamically adjusted in most transducers.

Question 4

A hyperechoic artifact that appears as a bright line or band posterior to a highly reflective surface, caused by reverberation between two strong reflectors, is called:

Accepted Answer

Reverberation artifact

Answer

Reverberation artifacts result from echoes bouncing multiple times between two strong reflectors, creating equally spaced bright lines deep to the true interface.

Question 5

Acoustic shadowing posterior to a gallstone is caused by:

Accepted Answer

Total reflection and high attenuation by the stone preventing sound transmission

Answer

Calcifications strongly reflect and absorb sound, so little energy passes through to deeper tissues, producing a dark shadow posteriorly.

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI Image Formation and Processing 3