Calculate Pourcelot RI for three Doppler waveforms measured from the same named vessel, segment, and acquisition protocol, then report the arithmetic mean, range, and sample standard deviation. This is a descriptive repeatability summary, not a reference-range comparison, diagnosis, or estimate of measurement uncertainty.
Measurement disclaimer: Use three technically acceptable waveform pairs from the same named vessel, segment, side, and protocol. This descriptive summary is not a diagnosis or treatment recommendation.
Repeated-Waveform Resistive Index Formula
This calculator applies the Pourcelot resistive index formula separately to three Doppler waveforms, then reports the arithmetic mean, range, and sample standard deviation of those three RI values.
- PSV is peak systolic velocity.
- EDV is end-diastolic velocity.
- RI is unitless because both velocities use the same unit.
- s is the descriptive sample standard deviation of the three entered RI values.
Measurement Requirements
Use three technically acceptable waveforms from the same named vessel, segment, side, patient state, and acquisition protocol. Do not average values from different organs, vessels, sides, or examination settings. Enter every PSV and EDV in the same velocity unit.
The range and sample standard deviation show how these three entered values differ. They do not quantify all measurement uncertainty and do not establish whether a result is normal or abnormal.
Interpretation Limits
Resistive index depends on the vascular bed, organ, hemodynamics, age, patient condition, waveform sampling, and equipment technique. There is no single universal RI cutoff that can diagnose stenosis, rejection, fibrosis, or another condition across all applications. A qualified clinician or sonographer should interpret the original waveforms and the protocol-specific context.
Frequently Asked Questions
Why does this calculator require three waveform pairs?
This page is intentionally limited to a repeated-measurement summary. Use the separate Doppler Resistance Index Calculator for a single waveform or reverse algebra.
Can EDV be negative?
Negative EDV can occur with reversed diastolic flow and may produce RI above 1. The clinical meaning depends on the vessel and waveform context.
Is the sample standard deviation a diagnostic result?
No. It is only a descriptive statistic for the three RI values entered here.
