SPI_통합영어2.

Increasing the dynamic range setting affects the ultrasound image by:

• Increasing image brightness
• Decreasing image contrast
• Improving spatial resolution
• Rejecting low-level echoes
• Improving signal-to-noise ratio

Answer explanation

A wider dynamic range lowers contrast because more echo levels are displayed.

After increasing sector width, how to preserve temporal resolution?

• Increase bit depth
• Increase scan lines
• Decrease matrix pixels
• Decrease number of focal zones
• Decrease PRF

Answer explanation

Fewer focal zones = fewer pulses per frame = faster image acquisition.

The term signal-to-noise ratio denotes:

• The ratio of the electronic noise to the radiofrequency noise
• The ratio of system power to weakest signal
• The relative amplitude of the signal to the noise
• Ratio of largest to smallest signal
• Ratio of transducer frequency to echo intensity

Answer explanation

Signal-to-noise ratio (SNR) refers to signal strength relative to background noise.

What effect will you see in the image if you increase the reject level?

• Increased number of shades of gray
• Decreased low-level echoes
• Decreased frame rate
• Decreased scanning depth
• Decreased amplitude of brightest grays

Answer explanation

Rejection removes low-amplitude echoes, cleaning up noise but possibly losing weak signals.

What is a disadvantage of a water-path scanner?

• It reduces axial resolution
• Poor elevational resolution
• Bubbles can inhibit transmission
• Only useful with low frequencies
• Fluid path increases mechanical index

Answer explanation

Air bubbles in the water path can block sound transmission, reducing image quality.

For accurate distance measurement in a phantom, the propagation speed must be:

• 13 μs/cm
• 1.54 m/s
• 1540 m/s
• Half the speed of sound
• Twice the soft tissue speed

Answer explanation

Ultrasound systems are calibrated for 1540 m/s – the average speed in soft tissue.

A typical value for the duty factor in diagnostic sonographic imaging is:

• 80%–100%
• 50%–75%
• 25%–45%
• 5%–20%
• 0.1%–1%

Answer explanation

Diagnostic ultrasound uses pulsed waves with very low duty factors, typically 0.1%–1%.

An M-mode display is most commonly used for what type of ultrasound imaging?

• Small parts
• Abdominal
• Cardiac
• Vascular
• Ophthalmologic

Answer explanation

M-mode is ideal for visualizing rapid motion, such as heart valve movements.

You have increased the output power by 10 dB. The signal intensity has:

• Doubled
• Tripled
• Quadrupled
• Increased by a factor of 10
• Increased by a factor of 100

Answer explanation

A 10 dB increase corresponds to a tenfold increase in intensity.

During an abdominal ultrasound study, which control most closely affects patient exposure?

• Receiver overall gain
• TGC
• Dynamic range
• Reject
• Output power

Answer explanation

Output power adjusts the strength of transmitted energy, directly influencing patient exposure.