Which post-injection PSV value range is considered reduced?

• A. <25 cm/s
• B. 25-29 cm/s
• C. 30-39 cm/s
• D. 40-50 cm/s

Answer: (A)

Understanding what constitutes a reduced post-injection peak systolic velocity helps you gauge arterial inflow after an intervention or bolus. PSV reflects the highest speed of blood flow during systole; after an injection, the expected perfusion transiently increases, so a lower-than-expected peak velocity indicates reduced flow to the tissue. A value below 25 cm/s is considered reduced because it falls below typical normal ranges for many vessels and protocols, signaling diminished arterial inflow. The other ranges listed (higher values) would be interpreted as normal or closer to normal perfusion rather than reduced. Keep in mind that exact cutoffs can vary with the vessel and technique, and factors like insonation angle can affect measured velocities.