Related Experiment Videos
Myocardial viability in cases with persistent perfusion defects on the dipyridamole thallium-201 scintigram. A
M Nakayama1, S Ohkawa, M Tanno
1Department of Nuclear Medicine and Radiological Sciences, Tokyo Metropolitan Geriatric Hospital, Japan.
Insights
Persistent perfusion defects on dipyridamole-stress thallium scintigraphy may overestimate myocardial infarction. Regional thallium uptake helps differentiate true infarction from other defects, improving diagnostic accuracy.
Area of Science:
- Cardiology
- Nuclear Medicine
- Pathology
Background:
- Dipyridamole-stress thallium scintigraphy is used to assess myocardial perfusion.
- Persistent perfusion defects can indicate myocardial infarction, but their accuracy needs validation.
Purpose of the Study:
- To determine the incidence of myocardial infarction in persistent perfusion defects identified by dipyridamole-stress thallium scintigraphy.
- To evaluate if regional thallium uptake in scintigraphic defects predicts infarction presence.
Main Methods:
- Comparison of autopsy findings with dipyridamole myocardial scintigrams in 27 patients.
- Quantification of regional thallium uptake and myocardial fibrosis in autopsy specimens.
Main Results:
- 40% of persistent defects on scintigraphy did not show infarction at autopsy.
- Regional thallium-201 uptake < 50% predicted infarction with 82% sensitivity and 80% specificity.
- A negative linear correlation (r = -0.67) was found between thallium uptake and fibrosis.
Conclusions:
- Perfusion defects in dipyridamole-stress testing may overestimate myocardial infarction.
- Regional thallium-201 activity aids in distinguishing true infarction from other perfusion defects.
Abstract:
The aim of this study was to assess the incidence of myocardial infarction among persistent perfusion defects in dipyridamole-stress thallium scintigraphy by inspecting autopsied hearts and to evaluate whether the regional thallium activity of a scintigraphic defect can predict the presence of infarction. Autopsied hearts were compared with dipyridamole myocardial scintigrams undertaken during life in 27 patients (mean age 85 +/- 8 years). The time interval from stress testing until death was 428 +/- 351 days. Regional thallium uptake of delayed perfusion defect was calculated on the short axis images. The grade of regional myocardial fibrosis in autopsy specimens was also quantified to correlate with the corresponding regional thallium uptake. In 6 of 15 (40%) regions with persistent defects on the scintigram, myocardial infarction was not found at autopsy. Regional thallium-201 uptake of delayed defects < 50% diagnosed infarction with a sensitivity of 82% and a specificity of 80%. A linear correlation (r = -0.67) was observed between percent thallium-201 uptake and the degree of myocardial fibrosis. In conclusion, perfusion defects at 4-hour imaging in dipyridamole-stress testing may overestimate the presence of myocardial infarction and regional thallium-201 activity is helpful in distinguishing between defects with and without infarction.