Pulse repetition period (PRP) is defined as what?

• A. Time from start of one pulse to start of next
• B. Time from start of echo to end of pulse
• C. Pulse duration
• D. Imaging depth

Answer: (A)

PRP is the time interval from the start of one ultrasound pulse to the start of the next pulse. This window covers the transmit time (the pulse itself) plus the listening time for echoes returning from the deepest depth being imaged. After this period, the next pulse is fired, so PRP and how often pulses are sent are linked: longer PRP means lower pulse repetition frequency. The other options describe different quantities: the pulse duration is just how long a single pulse lasts, and imaging depth is a separate parameter related to PRP but not its definition. The time from the start of an echo to the end of the pulse isn’t a standard metric in this context.