All of the following will improve temporal resolution EXCEPT:

• A. Increased line density
• B. Single rather than multi focus
• C. Higher frame rate
• D. Shallower depth of field

Answer: (A)

Temporal resolution is about how quickly successive ultrasound frames can be acquired, so the goal is to shorten the time needed to form a frame. Higher frame rate does just that, directly increasing how many frames you can display per second. Using a single focal zone rather than multiple focuses reduces the amount of transmit/receive work per line, letting the system push more frames per second. Imaging at a shallower depth confines the data set to a smaller range, which also reduces the per-frame data and increases frame rate. Increasing line density, on the other hand, adds more scan lines per frame, requiring more time to acquire and thereby lowering the frame rate and temporal resolution. So the option that will not improve temporal resolution is increasing line density.