Simultaneous measurement of left ventricular function and myocardial perfusion during a single exercise test: dual isotope imaging with gold-195 m and thallium-201

The state of left ventricular function and myocardial perfusionare important determinants of prognosis in patients with coronaryartery disease and information on both can be valuable for planningindividual patient management. We have studied the feasibilityof simultaneous measurement of left ventricular ejection fractionwith ultra short-lived gold-195 m (half life 30.5 seconds) andmyocardial perfusion with thallium-201, at rest and after exercisewith a single-crystal gamma camera. The results with first-passradionuclide angiocardiography (RNA) using gold-195 m at restwere reproducible and agreed closely with the results obtainedusing technetium-99 m equilibrium radionuclide angiocardiography(r = 0.93). Ejection fraction by firstpass gold-195 m RNA duringsemi-supine ergometric exercise decreased by >5% in 13 outof 18patients with coronary artery disease and stable angina.Simultaneous myocardial imaging with thallium-201 was abnormalin all patients. The change in regional wall motion abnormalityscore during exercise correlated with the change in myocardialperfusion (r = 0.71, P<0.01) and with the change in globalleft ventricular ejection fraction (r = 0.77, P<0.001). Thewidely differing energy levels and half-lives of gold-195 mand thallium-201 made it possible to separate clearly the imagesdue to each radionuclide. This study has demonstrated the feasibilityof simultaneous or sequential assessment of left ventricularfunction and myocardial perfusion during a single exercise test,a technique which can offer advantages in clinical evaluationof patients with coronary artery disease.