If the frame rate is too slow for adequate temporal resolution, what action could you take to improve frame rate?

• A. Reduce the number of transmit focal zones
• B. Increase the scan line density
• C. Increase the scanning depth
• D. Decrease the dynamic range

Answer: (A)

Temporal resolution depends on how fast each frame is acquired. When multiple transmit focal zones are used, the system must emit and receive additional focused pulses for each line, which takes extra time and slows the frame rate. Reducing the number of focal zones per line cuts the time needed to complete a frame, so frames come out faster and temporal resolution improves. This is a trade-off, because fewer focal zones can lessen lateral beam focusing and image sharpness. The other options would not increase frame rate: deeper scanning depth lengthens the echolocation cycle, higher scan line density adds more lines to each frame, and changing dynamic range affects contrast, not the time to acquire data.