A COMPARISON OF THE REDISTRIBUTION AND REINJECTION TECHNIQUES IN DIPYRIDAMOLE-THALLIUM TOMOGRAPHY

The effect of the injection of additional thallium after a redistribut ion study and prior to a further resting study was evaluated in 21 pat ients with angiographically proven coronary artery disease. Using dipy ridamole as the stress mechanism, the studies were carried out tomogra phically and the results analysed quantitatively with the Bullseye tec hnique. Two patients had normal scans. Of the remaining 19, 11 patient s had a perfusion defect which appeared irreversible on redistribution imaging. However, six of these patients demonstrated improved or norm al uptake after the second injection of thallium. Of the eight patient s with a reversible defect, two revealed considerably greater reversib ility after reinjection. These results indicate that the reinjection o f thallium prior to the resting study significantly (P < 0.02) improve s the detection rate of ischaemia during dipyridamole thallium tomogra phy.