If the manufacturer increases the number of scan lines per frame, which may have to be decreased?

• A. Frame rate
• B. Imaging depth
• C. Frequency
• D. Sector angle

Answer: (A)

Increasing the number of scan lines per frame means more data has to be collected for each image. Each line requires a complete sweep through the imaging depth, so adding lines takes more time to assemble one frame. With the same pulse timing and speed of sound, that extra time reduces how many frames can be produced each second, lowering the frame rate. Other factors like imaging depth, transmit frequency, or sector width influence timing in different ways, but the direct consequence of more lines per frame is a decreased frame rate.