Described herein are methods and systems for calculating a corrected Fractional Flow Reserve (FFR). An illustrative method includes delivering a first pressure sensing device including a pressure sensor to a location in a blood vessel having a stenosis, positioning the pressure sensor distal to the stenosis, measuring the distal pressure, measuring the proximal pressure, and calculating a corrected FFR using the measured proximal and distal pressures and applying a correction factor or correction equation. The corrected FFR may approximate a FFR that would have been obtained if the pressure measured downstream of the stenosis was measured using a second pressure sensing device having a second maximum cross-sectional area in a distal portion of the second pressure sensing device that is different from the first maximum cross-sectional area.
