Patent ID: 8715200

Claim:
A system for determining a blood flow in an individual coronary artery of a patient, comprising: a sensor guide wire having a distal portion provided with a guide wire sensor and being configured for positioning in the individual coronary artery; an infusion catheter configured for positioning in the individual coronary artery and configured for injecting an indicator fluid into the individual coronary artery; a monitoring device for transforming an output temperature signal from the guide wire sensor into a temperature of medium surrounding the sensor; and a device configured to be connected to the infusion catheter for delivering a cold indicator fluid from a reservoir into the individual coronary artery, wherein the monitoring device is configured to measure a mixture temperature of a mixture of blood and indicator fluid using the guide wire sensor, wherein the monitoring device is configured to calculate the blood flow by a formula, wherein the formula used for calculating the blood flow is: Q b = Q k ⁢ T k - T b T - T b where Q b is the blood flow, Q k is a known infusion rate of the indicator fluid, T k is a known or measurable temperature of the indicator fluid, T b is a measured blood temperature, and T is the measured mixture temperature.