Lower BNR indicates what about the beam?

Lower BNR indicates what about the beam?

• A. More uniform beam
• B. Less uniform beam
• C. Greater attenuation
• D. Higher frequency

Answer: (A)

Lower BNR means a more uniform beam. BNR, or beam nonuniformity ratio, measures how evenly the ultrasound beam illuminates the image. A smaller ratio indicates less variation in brightness across the beam, so the image appears more uniform with fewer hot or cold spots. Attenuation and frequency relate to energy loss and penetration depth, not the beam’s uniformity, so they don’t describe the meaning of BNR.

Lower BNR means a more uniform beam. BNR, or beam nonuniformity ratio, measures how evenly the ultrasound beam illuminates the image. A smaller ratio indicates less variation in brightness across the beam, so the image appears more uniform with fewer hot or cold spots. Attenuation and frequency relate to energy loss and penetration depth, not the beam’s uniformity, so they don’t describe the meaning of BNR.