Measurement of regional myocardial blood flow by intracoronary arterial injection of 133Xe

201Tl myocardial perfusion imaging (MPI) has been established as a noninvasive method to evaluate myocardial blood flow distribution, which is a function of myocardial mass and blood flow. To measure the blood flow specifically, a washout process of 133Xe was analyzed to calculate the specific flow in each regional element, that is regional myocardial blood flow (RMBF). The RMBF was expressed in a form of spacial distribution, so-called functional image, and was compared with the 201Tl MPI. 30 cases including 5 with normal or mild coronary artery disease (CAD) (Group I), 10 with severe CAD (Group II) and 15 with hypertrophic or congestive cardiomyopathy (Group III) were studied. Following coronary angiography, 133Xe in saline solution was injected into the coronary artery and the washout process was imaged to be analyzed during initial 40 seconds in LAO 300 by a multicrystal gamma camera. RMBF in each regional element was calculated according to the initial slope method to be analyzed as the functional image' 201Tl MPI was also performed in RAO 300, anterior, LAO 300, LAO 450, LAO 600 and left lateral position. Regional distribution of these two methods concerning myocardial perfusion were compared each other. These observed to be reasonable correlation between RMBF and MPI of Group I and Group II. However, in several cases of Group III, abnormal perfusion of hypertrophied mass was suggested to be present in the RMBF image, which could not be resolved in 201Tl MPI but only hypertrophied mass was visualized. In conclusion, present type of imaging provided supplemental information to the conventional 201Tl MPI. (author)