What does a lower BNR indicate?

What does a lower BNR indicate?

• A. A more uniform beam
• B. A more divergent beam
• C. Higher peak intensity
• D. Greater tissue heating

Answer: (A)

BNR, or beam nonuniformity ratio, reflects how uniform the ultrasound beam is across its profile. A lower BNR means the beam’s intensity varies less from point to point, so energy is distributed more evenly and there are fewer hot spots. This yields a more uniform image and reduces the risk of localized tissue heating associated with intense focal spots. Divergence describes how the beam spreads, which isn’t directly dictated by BNR. Higher peak intensity isn’t guaranteed by a lower BNR, since uniformity doesn’t imply a higher maximum; and while lower BNR can lessen hotspot heating, overall heating depends on the absolute energy delivered.

BNR, or beam nonuniformity ratio, reflects how uniform the ultrasound beam is across its profile. A lower BNR means the beam’s intensity varies less from point to point, so energy is distributed more evenly and there are fewer hot spots. This yields a more uniform image and reduces the risk of localized tissue heating associated with intense focal spots. Divergence describes how the beam spreads, which isn’t directly dictated by BNR. Higher peak intensity isn’t guaranteed by a lower BNR, since uniformity doesn’t imply a higher maximum; and while lower BNR can lessen hotspot heating, overall heating depends on the absolute energy delivered.