Measurement of regional myocardial blood flow in dogs using a catheter semiconductor radiation detector

Simultaneous total left coronary and regional myocardial blood flow were measured by injecting 85Kr into the left coronary artery and recording its clearance using a precordial gamma detector and a catheter tip beta detector (CASRAD) placed directly on selected regions of the myocardium. There were no significant differences between total left coronary (175 ml.100 g−1/min) measured by the precordial gamma detection and regional myocardial blood flow (183 ml.100 g−1/min) determined in the area of the left anterior descending coronary artery (LAD) by the beta detector in five open chest dogs. After ligation of the LAD regional clearance of 85Kr ceased in the area of myocardium distal to the ligation while total coronary blood flow decreased only slightly from 152 to 126 ml.100 g−1/min. Measurement of regional myocardial blood flow by CASRAD may be of value in determining the extent of myocardial ischaemia in experimental animals and assessing the effect of therapeutic interventions.