Patent ID: 6986744

Claim:
A method for quantitatively measuring a reduced stenosis induced flow change, comprising: (a) inserting a catheter and a blood property sensor into a vessel having a brood flow corresponding to the stenosis; (b) introducing from an indicator source a first change in a blood property in a blood flow outside the catheter at a fixed distance from the blood property sensor and upstream of the blood property sensor; (c) detecting passage of the first change in the blood property at the blood property sensor; (d) reducing the stenosis in the vessel; (e) introducing from the indicator source a second change in the blood property upstream of the sensor; (f) detecting passage of the second change in the blood property at the blood property sensor; and (g) determining at a controller connected to the indicator source and the sensor a change in blood flow corresponding to (i) the detected passage of the first change in the blood property and (ii) the second change in the blood property.