PISA is an acronym used in MR assessment. What does PISA stand for?

• A. Proximal Isovelocity Surface Area
• B. Proximal Isovelocity Simulation Area
• C. Proximal Isokinetic Surface Area
• D. Proximal Isometric Surface Analysis

Answer: (A)

The idea behind this item is the PISA method used to quantify mitral regurgitation. PISA stands for Proximal Isovelocity Surface Area. In MR, the flow converges toward the regurgitant orifice and creates a surface where the velocity is the same (an isovelocity surface) very near the orifice. That flow region is roughly hemispherical, so by measuring the radius of that hemispheric shell at a known aliasing velocity, you can estimate the flow rate across the orifice with Q ≈ 2πr^2 × aliasing velocity. From there, you derive the effective regurgitant orifice area (EROA) as EROA = Q / Vmax of the MR jet, and the regurgitant volume as EROA × VTI of the MR jet. The other options don’t reflect the real terminology or concept of this method.