A system for calculating a corrected Fractional Flow Reserve associated with a stenosis in a blood vessel, the system comprising: a first pressure sensing device configured for placement within the blood vessel to measure pressure within the blood vessel downstream of the stenosis, the first pressure sensing device having a proximal portion and a distal portion, the distal portion having a maximum cross-sectional area, and a pressure sensor; and a processing device in communication with the first pressure sensing device, characterized in that the system further comprises a memory component storing a data set comprising a group of at least two correction factors or correction equations, each correction factor or correction equation corresponding to a maximum cross-sectional area of a distal portion of a second pressure sensing device that is different from the maximum cross-sectional area of the distal portion of the first pressure sensing device, and wherein: the processing device is configured to select a correction factor or correction equation from the group based upon the maximum cross-sectional area of the distal portion of the first pressure sensing device and calculate a corrected FFR using the selected correction factor or correction equation and the pressure measured downstream of the stenosis by the sensor of the first pressure sensing device; and wherein the corrected FFR approximates a FFR that would have been obtained if the pressure measured downstream of the stenosis was measured using the second pressure sensing device. a first pressure sensing device configured for placement within the blood vessel to measure pressure within the blood vessel downstream of the stenosis, the first pressure sensing device having a proximal portion and a distal portion, the distal portion having a maximum cross-sectional area, and a pressure sensor; and a processing device in communication with the first pressure sensing device, characterized in that the system further comprises a memory component storing a data set comprising a group of at least two correction factors or correction equations, each correction factor or correction equation corresponding to a maximum cross-sectional area of a distal portion of a second pressure sensing device that is different from the maximum cross-sectional area of the distal portion of the first pressure sensing device, and wherein: the processing device is configured to select a correction factor or correction equation from the group based upon the maximum cross-sectional area of the distal portion of the first pressure sensing device and calculate a corrected FFR using the selected correction factor or correction equation and the pressure measured downstream of the stenosis by the sensor of the first pressure sensing device; and wherein the corrected FFR approximates a FFR that would have been obtained if the pressure measured downstream of the stenosis was measured using the second pressure sensing device. the processing device is configured to select a correction factor or correction equation from the group based upon the maximum cross-sectional area of the distal portion of the first pressure sensing device and calculate a corrected FFR using the selected correction factor or correction equation and the pressure measured downstream of the stenosis by the sensor of the first pressure sensing device; and wherein the corrected FFR approximates a FFR that would have been obtained if the pressure measured downstream of the stenosis was measured using the second pressure sensing device.