Which effect occurs on the ultrasound image when you increase the reject level?

Which effect occurs on the ultrasound image when you increase the reject level?

• A. Decreased frame rate
• B. Decreased low-level echoes
• C. Decreased scanning depth
• D. Increased number of shades of gray

Answer: (B)

Raising the reject level filters out weaker signals so only echoes above a certain amplitude are displayed. That means faint, low-level echoes disappear from the image, which is described as a decrease in low-level echoes. The reject control mainly affects noise and very subtle interfaces, not how fast images are acquired (frame rate) or how deep you can scan (scanning depth). It also tends to reduce the number of visible grayscale steps, since faint echoes are removed, rather than increasing the range of shades.

Raising the reject level filters out weaker signals so only echoes above a certain amplitude are displayed. That means faint, low-level echoes disappear from the image, which is described as a decrease in low-level echoes. The reject control mainly affects noise and very subtle interfaces, not how fast images are acquired (frame rate) or how deep you can scan (scanning depth). It also tends to reduce the number of visible grayscale steps, since faint echoes are removed, rather than increasing the range of shades.