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Technetium 99m-labeled tetrofosmin myocardial tomography in patients with coronary artery disease: comparison between
A Cuocolo1, E Nicolai, A Soricelli
1Cattedra di Medicina Nucleare, Cenrro per la Medicina Nucleare del CNR, Napoli, Italy.
Insights
Pharmacologic coronary vasodilation with adenosine and exercise 99mTc-labeled tetrofosmin myocardial tomography show similar diagnostic accuracy for coronary artery disease (CAD). Both methods effectively detect CAD in patients unable to exercise, offering comparable sensitivity and specificity.
Area of Science:
- Cardiology
- Nuclear Medicine
- Radiology
Background:
- Pharmacologic coronary vasodilation using adenosine with myocardial scintigraphy is a key diagnostic tool for coronary artery disease (CAD) in non-exercising patients.
- Exercise-based 99mTc-labeled tetrofosmin cardiac imaging is also effective for CAD detection.
- Comparative data between adenosine and exercise 99mTc-labeled tetrofosmin tests in the same patients were previously lacking.
Purpose of the Study:
- To compare the diagnostic performance of adenosine-induced vasodilation versus dynamic exercise stress testing using 99mTc-labeled tetrofosmin myocardial tomography in patients with suspected or known CAD.
- To evaluate the agreement and concordance between the two imaging modalities for detecting and localizing CAD.
Main Methods:
- 41 patients with suspected or known CAD underwent coronary angiography and three 99mTc-labeled tetrofosmin myocardial tomography scans on separate days: rest, bicycle exercise, and adenosine infusion.
- Quantitative analysis of 902 myocardial segments was performed to assess tracer uptake.
- Hemodynamic parameters including heart rate and blood pressure were monitored.
Main Results:
- Adenosine infusion significantly increased heart rate but did not alter blood pressure, while exercise resulted in a higher double product.
- Quantitative analysis showed 100% agreement on the presence of abnormal myocardial perfusion between adenosine and exercise.
- Segmental agreement for tracer uptake was 82% (kappa=0.66), and concordance for perfusion status was 90% (kappa=0.80).
- Sensitivity and specificity for detecting stenosed vessels were comparable between adenosine and exercise stress testing.
Conclusions:
- Adenosine and dynamic exercise 99mTc-labeled tetrofosmin single-photon emission computed tomographic imaging yield similar diagnostic information for CAD.
- Despite differing hemodynamic effects, both methods are effective in the diagnosis and localization of coronary artery disease.
- These findings support the use of adenosine stress testing as a viable alternative for patients unable to perform dynamic exercise.
Background:
Pharmacologic coronary vasodilation with adenosine, combined with myocardial scintigraphy, is a useful test for the diagnosis of coronary artery disease (CAD) in patients unable to exercise. It has been demonstrated recently that exercise 99mTc-labeled tetrofosmin cardiac imaging can be used for the detection of CAD. However, no data are available comparing 99mTc-labeled tetrofosmin adenosine and exercise tests in the same patients.
Methods And Results:
The results of adenosine and exercise 99mTc-labeled tetrofosmin myocardial tomography were compared in 41 patients (37 men and four women; mean age 53 +/- 8 years) with suspected or known CAD who underwent coronary angiography. All patients were submitted, on separate days, to three injections of 99mTc-labeled tetrofosmin (740 MBq intravenously): one at rest, one during bicycle exercise, and one during adenosine infusion (140 micrograms/kg/min for 6 minutes with injection of 99mTc-labeled tetrofosmin at 4 minutes). A total of 902 myocardial segments were analyzed quantitatively. One patient had normal coronary vessels, 19 patients had single-vessel CAD, 12 patients had two-vessel CAD, and nine patients had three-vessel CAD (> 50% coronary stenosis) on coronary angiography. Adenosine induced a significant increase in heart rate (88 +/- 16 beats/min at peak vs 72 +/- 11 beats/min at rest; p < 0.01). Systolic and diastolic blood pressure was not significantly different after adenosine infusion compared with rest. Double product was 22931 +/- 7039 at peak exercise and 11229 +/- 3413 after adenosine (p < 0.01). Agreement on the presence of abnormal single-photon emission computed tomography by adenosine and exercise was 100% by quantitative analysis. In all segments a significant relationship between exercise and adenosine 99mTc-99m-labeled tetrofosmin uptake was observed (r = 0.90; p < 0.001). Segmental agreement for regional 99mTc-labeled tetrofosmin uptake score between exercise and adenosine was observed in 737 (82%) of the 902 segments (kappa value of 0.66). Concordance between the two studies for identification of perfusion status was observed in 809 (90%) of the segments (kappa value of 0.80). Sensitivity and specificity for detection of stenosed vessels were not different for dynamic exercise stress testing and adenosine 99mTc-labeled tetrofosmin cardiac tomography.
Conclusions:
Despite different hemodynamic effects, adenosine and dynamic exercise 99mTc-labeled tetrofosmin single-photon emission computed tomographic imaging provides similar information in the diagnosis and localization of CAD.