Which of the following is NOT used to describe a single ultrasound pulse?

• A. Pulse Duration
• B. Wavelength
• C. Pulse Length
• D. Pulse Repetition Frequency

Answer: (D)

The key idea is distinguishing properties that describe an individual pulse from those that describe how often pulses are sent. A single ultrasound pulse has a duration (the time the pulse is actively transmitted), a wavelength (the distance of one cycle, set by sound speed and frequency), and a pulse length (the spatial extent of the pulse, essentially cycles times wavelength). Pulse repetition frequency, on the other hand, is the rate at which entire pulses are emitted per second. It describes the sequence of pulses, not a single pulse itself. Because the question asks which does not describe a single pulse, pulse repetition frequency is the best choice. It affects how often pulses are sent and influences frame rate and maximum imaging depth, but it isn’t a property of an individual pulse.