Which imaging type is associated with longer PRP, lower PRF, and lower duty factor?

In ultrasound imaging, the types associated with longer Pulse Repetition Period (PRP), lower Pulse Repetition Frequency (PRF), and lower duty factor are typically those involving deeper imaging.

When imaging at greater depths, the system requires a longer PRP to accommodate the increased time it takes for the sound waves to travel to the deeper structures and return to the transducer. This longer travel time results in a longer PRP, which consequently lowers the PRF, since PRF is inversely related to PRP. Therefore, when the duty factor is calculated—the ratio of the time the system is actively transmitting sound waves to the total time in the imaging cycle—this also becomes lower, as the increased duration of the listening phase (waiting for echoes) is not matched by an increase in transmission time.

In contrast, shallow imaging utilizes shorter PRPs and higher PRFs due to the reduced time needed for sound waves to travel to and from the target structures. This results in a higher duty factor for shallow imaging, which is the opposite of what is experienced in deep imaging scenarios. Thus, the characteristics of deeper imaging directly correlate with longer PRP, lower PRF, and lower duty factor, making it the correct choice in this context.