Imaging frame rate decreases when you:

• A. Decrease frequency
• B. Increase dynamic range
• C. Increase frame averaging
• D. Increase sector width

Answer: (D)

Frame rate is tied to how long it takes to acquire one frame. A frame is built from many scan lines across the imaged area, so widening the sector means more lines must be sampled to cover the broader angle. Each line requires a separate transmit/receive event, which adds time to complete the frame. More time per frame means fewer frames per second, so the frame rate drops when the sector width increases. The other factors don’t change the number of lines needed or the time to acquire them in the same way: lowering frequency mainly affects penetration and resolution but not speed; increasing dynamic range changes display mapping; increasing frame averaging adds up multiple frames before display, reducing the effective frame rate.