Temporal resolution is determined by which of the following?

• A. Frame rate
• B. Depth
• C. Frequency
• D. Contrast

Answer: (A)

Temporal resolution is about how well moving structures can be followed over time, which depends on how many frames the system can produce each second. The best answer is frame rate, because more frames per second means less time between frames and crisper depiction of motion. Frame rate decreases when imaging depth is increased (longer travel times for echoes), or when more lines are used per frame or a wider sector is employed, all of which slow down how fast frames are created. Frequency affects image detail and penetration but does not by itself set how many frames are produced per second, and contrast changes tissue brightness rather than the speed of frame acquisition. So the ability to capture rapid motion hinges on frame rate.