Pulse Repetition Frequency Settings in Ultrasound

PRF Settings by Anatomical Region

The American College of Rheumatology recommends a Pulse Repetition Frequency (PRF) range of 2-7 kHz for temporal arteries and 3-8 kHz for extracranial supra-aortic arteries 1
When imaging blood vessels with color Doppler, the PRF should be optimized to avoid underfilling or overfilling of the vessel lumen, as recommended by the American College of Rheumatology 1, 2
Flow parameters should be adjusted to maximize sensitivity for detecting vessels with low-velocity flow in the bowel wall, according to the European Crohn's and Colitis Organisation 3

Lower frequencies provide greater tissue penetration but reduced resolution, making them suitable for deeper structures and obese patients, as noted by the American College of Rheumatology 6
Higher frequencies (≥15 MHz for temporal arteries, 7-15 MHz for extracranial arteries) provide better resolution but limited penetration, as recommended by the American College of Rheumatology 1, 2

For microbubble-based applications, the optimal frequency range is between 0.3-3 MHz, which corresponds to the resonance frequencies of commercial microbubbles, according to the International Society for Therapeutic Ultrasound 4, 5
For trans-scleral drug delivery, lower frequencies significantly improve penetration depth, as noted by the International Society for Therapeutic Ultrasound 4, 7

Using inappropriate PRF settings can lead to either underfilling or overfilling, as warned by the American College of Rheumatology 1, 2
Higher frequency transducers (>5 MHz) produce inadequate images in obese patients due to limited penetration depth, according to the American College of Rheumatology 6