A method of predicting outcome of treatment of a vessel of a patient, comprising: calculating a pressure ratio based on pressure measurements obtained from a first instrument and a second instrument positioned within the vessel of the patient, while the second instrument is moved longitudinally through the vessel and the first instrument remains stationary within the vessel; co-registering the calculated pressure ratio with obtained angiography data; outputting to a display device a visual representation including: the calculated pressure ratio curve associated with locations within the vessel based on the co-registered angiographic data along with a graphical representation of at least one stent , and/or the calculated pressure ratio overlaid on the angiography data along with the graphical representation of the at least one stent positioned in the vessel; receiving a user input to modify a position and/or a length of the at least one stent to a virtual/simulated situation; determining a predicted pressure ratio for the virtual/simulated situation based on the modified position and/or length of the at least one stent, the calculated pressure ratio and the associated angiography data; outputting to the display device the predicted pressure ratio along with the modified position and/or length of the at least one stent; updating the visual representation , in response to the predicted pressure ratio and the modified position and/or length of the at least one stent for evaluating the predicted outcome of the treatment; and correlating the virtual/simulated characteristics of the graphical representation of the stent with the co-registered angiography data to determine real physiological parameters for the at least one stent to be deployed in the vessel. calculating a pressure ratio based on pressure measurements obtained from a first instrument and a second instrument positioned within the vessel of the patient, while the second instrument is moved longitudinally through the vessel and the first instrument remains stationary within the vessel; co-registering the calculated pressure ratio with obtained angiography data; outputting to a display device a visual representation including: the calculated pressure ratio curve associated with locations within the vessel based on the co-registered angiographic data along with a graphical representation of at least one stent , and/or the calculated pressure ratio overlaid on the angiography data along with the graphical representation of the at least one stent positioned in the vessel; the calculated pressure ratio curve associated with locations within the vessel based on the co-registered angiographic data along with a graphical representation of at least one stent , and/or the calculated pressure ratio overlaid on the angiography data along with the graphical representation of the at least one stent positioned in the vessel; receiving a user input to modify a position and/or a length of the at least one stent to a virtual/simulated situation; determining a predicted pressure ratio for the virtual/simulated situation based on the modified position and/or length of the at least one stent, the calculated pressure ratio and the associated angiography data; outputting to the display device the predicted pressure ratio along with the modified position and/or length of the at least one stent; updating the visual representation , in response to the predicted pressure ratio and the modified position and/or length of the at least one stent for evaluating the predicted outcome of the treatment; and correlating the virtual/simulated characteristics of the graphical representation of the stent with the co-registered angiography data to determine real physiological parameters for the at least one stent to be deployed in the vessel. <EOS>