Limitations

• PISA shape affected
  • by the aliasing velocity
  • in case of non-circular orifice
  • by systolic changes in regurgitant flow
  • by adjacent structures (flow constrainment)
• PISA is more a hemi-ellipse
• Errors in PISA radius measurement are Squared
• Inter-observer variability
• Not valid for multiple jets

Usefulness/Advantages

• Can be used in eccentric jet
• Not affected by the aetiology of MR or other valve leak
• Quantitative: estimate lesion severity (EROA) and volume overload (R Vol)
• Flow convergence at 50 cm/s alerts to significant MR