Intracoronary injections of the new radionuclide gold-195m

Preliminary results of 14 radionuclide injections in nine patients are discussed. The bolus of gold-195m is flushed into the coronary artery with 7 ml of 5% glucose at an injection rate of 5 ml/sec. During injection an electrocardiogram (ECG) is recorded immediately after injection, as well as the intracoronary arterial pressure. Two to four hours after examination, an ECG recording is repeated, and the next day serum enzymes are controlled. For evaluation the sequence of images during inflow and outflow from the coronary arteries was examined, the inflow usually corresponding to the two first cardiac cycles after injection. Two processing programs were developed: one program showing for each pixel the maximum count and the time of its occurrence, and the second one showing on functional images the rate of flow and the mean transit time (center of gravity) of inflow, inflow-outflow curves, respectively. On the latter images central coronary arteries and veins became visible. Normal and pathological flow distribution was shown on these functional images. The technique may become useful in the valuation of residual tissue perfusion after myocardial infarction