CCI Ultrasound Physics and Instrumentation 5

Question 1

The mechanical index (MI) displayed on an ultrasound machine is most closely associated with the risk of:

Accepted Answer

Cavitation and non-thermal mechanical bioeffects

Answer

MI = peak negative pressure / √frequency; higher MI values indicate greater potential for cavitation and non-thermal mechanical bioeffects.

Question 2

When sector width is reduced on a 2D echocardiographic image, the primary benefit is:

Accepted Answer

Increased frame rate

Answer

A narrower sector requires fewer scan lines per frame, allowing the system to update the image more frequently and increasing frame rate.

Question 3

Which artifact causes a structure to appear duplicated and displaced laterally in an ultrasound image?

Accepted Answer

Refraction artifact (ghost image)

Answer

Refraction at curved tissue interfaces bends the sound beam, causing the machine to misplace the returning echo and display a duplicate or displaced ghost image.

Question 4

In the context of transesophageal echocardiography (TEE), the higher image quality compared to transthoracic echo is mainly due to:

Accepted Answer

Elimination of chest wall and lung attenuation by placing the probe adjacent to the heart

Answer

The esophagus lies directly posterior to the heart, eliminating lung and chest wall attenuation and allowing higher frequency transducers that provide superior resolution.

Question 5

The Doppler shift frequency is directly proportional to which of the following?

Accepted Answer

The velocity of the moving reflector (blood cells)

Answer

The Doppler equation shows that Doppler shift = (2 × f × v × cos θ) / c; shift is directly proportional to velocity of the reflector.

CCI - Cardiovascular Credentialing International Practice Test

CCI - Cardiovascular Credentialing International Practice Test

CCI Ultrasound Physics and Instrumentation 5