Value of technetium Mibi to detect short lasting episodes of severe my ocardial ischaemia and to estimate the area at risk during coronary angioplasty

201Tl has been used for more than a decade in cardiology in spite of its physical properties, which are far from ideal. Other agents, with better physical characteristics, are desirable. Tc99m Mibi has become available. It is different from 201Tl not only because of a better energy, 140 (keV), shorter half-life (6 h), but also because it shows minimal redistribution; it can therefore be administered in a different location from where the nuclear investigation can be performed. In this study, we investigated the value of Tc99m Mibi to detect short-lasting episodes of ischaemia and to determine the area at risk during PTCA, by injecting the substrate in the catheterization laboratory during the first balloon inflation. The 13 patients studied, had single vessel disease, a normal resting ECG and a normal left ventricular contraction pattern. In eight, a PTCA was performed in the LAD, in three, in the circumflex, and in two, in the RCA. In 11 patients, a defect was seen in the single photon emission computer tomography images, which corresponds to the area supplied by the coronary artery, where flow was obstructed during PTCA. Tc99m Mibi is able to detect short-lasting episodes of ischaemia caused by a complete occlusion of the coronary artery. It is also of help to estimate the area at risk during PTCA.