Serial thallium-201 myocardial imaging after dipyridamole infusion: diagnostic utility in detecting coronary stenoses and relationship to regional wall motion.

Abstract

SUMMARY After a 4-minute i.v. dipyridamole infusion, 0.14 mg/kg/min, serial thallium-201 scans were obtained in 60 patients undergoing cardiac catheterization. Forty patients had significant (> 50% stenosis) coronary artery disease (CAD), and 20 patients had normal coronary arteries or trivial lesions. The images were graded qualitatively for thallium activity by three observers. Sensitivity was 93% (37 of 40) and specificity was 80% (16 of 20). The sensitivity and specificity of the thallium-201 study were not affected by the extent of CAD, the presence of Q waves, or propranolol therapy. Twenty-seven of 37 patients who had initial defects (73%) had complete thallium redistribution of one or more defects. Patient-by-patient analysis using a regression model of all patients showed that the fate of a segmental thallium defect predicted abnormal wall motion by angiography better than ECG Q waves. The presence of propranolol therapy or collaterals did not significantly affect the thallium redistribution results.We conclude that qualitative interpretation by multiple observers of thallium images after dipyridamole infusion is a highly sensitive and specific test for CAD. After dipyridamole, as with exercise stress, the extent of thallium redistribution is related to the degree of myocardial wall motion abnormality.PREVIOUS STUDIES have shown that exercise thallium-201 myocardial imaging can detect coronary artery disease (CAD).`1 In addition, thallium-201 redistribution shown by serial imaging can identify ischemic but viable myocardium.7-10 However, a standard maximal exercise stress test is not always possible for various reasons, including therapy with ,3 blockers, unstable anginal symptoms, poor physical condition and peripheral vascular disease. A method for evaluating myocardial perfusion and viability that does not require exercise would be valuable.Gould and co-workers"'-13 reported that dipyridamole given intravenously could lead to coronary vasodilation in normal vessels, but fixed coronary stenoses prevented or attenuated this response. The coronary flow response to dipyridamole was similar to that during exercise, but without the physiologic increase in myocardial oxygen demand. These and other investigators '46 have shown that in conjunction with a dipyridamole infusion, thallium-201 scans reliably detect CAD. 116 However, the significance of changes in thallium-201 distribution over time after dipyridamole infusion has not been investigated, and the impact of propranolol on the dipyridamole thallium-201 study has not been defined.Therefore, we sought to determine the significance

The safety of intravenous dipyridamole thallium myocardial perfusion imaging. Intravenous Dipyridamole Thallium Imaging Study Group.

“…This is in agreement with findings of previous investigations. [2][3][4]6 The study strongly supports the recommendation that parenteral aminophylline be readily available when intravenous dipyridamole-thallium scintigraphy is performed.…”

Safety of and Tolerance to Adenosine Infusion for Myocardial Perfusion Single-Photon Emission Computed Tomography in a Japanese Population

“…1 Dipyridamole in conjunction with thallium imaging has been widely used as an alternative to exercise for patients unable to perform adequate exercise stress testing. 2,3 However, side-effects caused by dipyridamole administration are frequent and can be life-threatening, because of its prolonged pharmacologic effect (15-30 min when administered intravenously), and it is often necessary to eliminate side-effects with intravenous aminophylline infusion. [4][5][6][7] Dipyridamole is thought to be an indirect coronary vasodilator, and it acts by blocking the cellular uptake of the primary vasodilator, adenosine, and leads to subsequent increases in myocardial and arterial wall adenosine concentrations.…”

Study of Coronary Flow Reserve with Intravenous Use of Microbubbles (Contrast Echocardiography) and Adenosine: Protocol for Clinical Application in Patients Suspected of Having Coronary Heart Disease

“…Techniques with pharmacological stress are widely used to diagnose coronary artery disease [53][54][55][56][57][58] . Dipyridamole is one of the most used drugs to cause myocardial ischemia with segmentary contraction abnormalities on two-dimensional echocardiography 58 , with sensitivity similar to that of thallium-201 myocardial perfusion scintigraphy.…”