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Regional concordance and discordance between rest thallium 201 and sestamibi imaging for assessing tissue viability:
P Marzullo1, G Sambuceti, O Parodi
1National Research Council Institute of Clinical Physiology, Pisa, Italy. marzullo@nsifc.ifc.pi.cnr.it
Insights
Rest thallium-201 (201Tl) uptake is a better indicator of myocardial viability than sestamibi in patients with coronary artery disease and infarction. Mismatched segments with sestamibi uptake but absent 201Tl uptake showed poor viability.
Area of Science:
- Cardiology
- Nuclear Medicine
- Diagnostic Imaging
Background:
- Assessing myocardial viability is crucial in managing coronary artery disease (CAD) patients post-myocardial infarction (MI).
- The added value of combining rest 201Tl and sestamibi scintigraphy for viability assessment in CAD remains under investigation.
Purpose of the Study:
- To evaluate the combined diagnostic utility of rest 201Tl and sestamibi scintigraphy in determining myocardial viability.
- To correlate scintigraphic findings with functional recovery after revascularization in patients with previous MI.
Main Methods:
- Quantitative rest sestamibi and 201Tl scintigraphy were performed on 22 patients with previous MI and regional dysfunction.
- All patients underwent revascularization, followed by repeat echocardiography 11 ± 2 weeks later.
- Analysis focused on dyssynergic segments, comparing scintigraphic uptake with echocardiographic wall motion improvement.
Main Results:
- Sestamibi and 201Tl showed concordant results in 80% of dyssynergic segments.
- Segments with maintained uptake of both tracers demonstrated improved contractility in 76% of cases.
- Segments with sestamibi/201Tl mismatch (24%) showed varied outcomes: normal sestamibi/abnormal 201Tl (12 segments) had poor improvement, while abnormal sestamibi/normal 201Tl (13 segments) showed good improvement.
Conclusions:
- While sestamibi and 201Tl uptake are often concordant, significant 201Tl uptake is a reliable indicator of myocardial viability.
- Maintained sestamibi uptake without 201Tl uptake is a poor predictor of viable myocardium in post-MI patients.
- The mismatch pattern, particularly normal sestamibi with absent 201Tl, suggests non-viable tissue.
Background:
Whether the combined analysis of rest 201Tl and sestamibi uptake provides additional information regarding myocardial viability in patients with coronary artery disease is still to be investigated.
Methods And Results:
To this aim we studied 22 patients with previous myocardial infarction and regional ventricular dysfunction by quantitative rest sestamibi and 201Tl scintigraphy. All patients underwent revascularization, and echocardiography was repeated 11 +/- 2 weeks later. Concordant results were obtained in 80 of 105 dyssynergic segments. Fifty-one segments showed normal and 29 abnormal activity. Follow-up echocardiography showed increased wall motion contractility in 76% of segments with maintained 201Tl and sestamibi uptake and in only 17% of segments characterized by subthreshold activities. Twenty-five segments, or 24%, showed sestamibi/201Tl mismatch. Eleven of 12 segments with normal sestamibi/abnormal 201Tl activity did not improve after revascularization, whereas 11 of 13 segments with abnormal sestamibi but normal 201Tl showed postoperative improvement of regional wall motion.
Conclusions:
In patients with previous myocardial infarction, sestamibi and 201Tl showed concordant results in most segments. However, in segments with mismatch a maintained sestamibi uptake was a poor indicator of tissue viability, whereas significant 201Tl uptake reflected tissue viability in most segments.