Assessment of myocardial blood flow by real-time infrared imaging

In order to evaluate the applicability of infrared imaging for the assessment of myocardial perfusion, 10 open-chested dogs were studied by a real-time infrared imaging system. The left anterior descending coronary artery was occluded for 90 min followed by 210 min of reperfusion. During the experiment, myocardial surface temperature was mapped by an infrared imaging system with a thermal resolution power of 0.1 degree C and correlated with regional myocardial blood flow measured using radiolabeled microspheres. Following the experiment, acute myocardial injury was evaluated using triphenyltetrazolium chloride staining. After 90 min of ischemia, there was a significant correlation between myocardial blood flow and myocardial surface temperature (R = 0.694, P less than 0.001). After reperfusion, temperature did not correlate with blood flow, but there was a significant correlation between temperature and ischemic myocardial injury (R = 0.551, P less than 0.05). Temperature changes during acute regional ischemia and reperfusion may be regulated by the changes in myocardial blood flow and myocardial metabolism. Temperature analysis using real-time infrared imaging may be a useful means for the evaluation of myocardial blood flow and myocardial injury during ischemia and reperfusion.