PISA EROA (Mitral Regurgitation)
Enter aliasing velocity, PISA radius, peak MR velocity, and MR VTI to compute flow rate, effective regurgitant orifice area, and regurgitant volume.
Nyquist limit from color Doppler (typically 30–40 cm/s).
Measure from regurgitant orifice to first aliasing boundary in mid-systole.
Continuous-wave Doppler peak velocity of MR jet.
Velocity time integral of MR jet from continuous-wave Doppler.
How to Use This Calculator
Acquire PISA measurements
Adjust color Doppler baseline to obtain hemispheric PISA, measure aliasing velocity and radius in mid-systole.
Record MR Doppler data
Measure the peak MR velocity and integrate the MR VTI using continuous-wave Doppler aligned with the regurgitant jet.
Interpret severity
Combine EROA, regurgitant volume, vena contracta, and qualitative assessment for comprehensive MR severity grading.
Formula
Flow rate = 2π × r² × Va
EROA = Flow rate ÷ Vmax
Regurgitant volume = EROA × MR VTI
Va = aliasing velocity (cm/s), r = PISA radius (cm), Vmax = peak MR velocity (cm/s).
Full Description
The PISA method estimates mitral regurgitation severity by assuming hemispheric flow convergence proximal to the regurgitant orifice. Regurgitant flow rate is derived from aliasing velocity, and dividing by peak MR velocity yields the effective regurgitant orifice area (EROA). Multiplying EROA by MR VTI provides regurgitant volume per beat.
Accurate measurements require optimizing color Doppler settings, aligning CW Doppler with the MR jet, and averaging multiple beats in atrial fibrillation. Severe MR is typically defined by EROA ≥ 0.40 cm² or regurgitant volume ≥ 60 mL/beat in primary MR (lower thresholds in secondary MR).
Frequently Asked Questions
What if the flow convergence is not hemispheric?
Elliptical or distorted PISA shapes reduce accuracy. Apply correction factors or supplement with other MR quantification methods.
How do dynamic MR jets affect calculations?
Functional MR or late-systolic MR may have variable orifices. Measure at peak regurgitation and interpret alongside qualitative findings.
Should I average multiple beats?
Yes, especially in arrhythmias. Average 3–5 beats (or more in atrial fibrillation) to reduce variability.
Can this be used for tricuspid regurgitation?
Yes, the same PISA principles apply but normal cutoffs differ. For TR, severe EROA is typically ≥0.40 cm².