Accuracy of detection of myocardial viability and residual infarct vessel stenoses with rest Tl-201 and adenosine Tc-99m sestamibi imaging after coronary reperfusion in dogs with experimental acute myocardial infarction
✍ Scribed by Kazuya Takehana; George A Beller; Mirta Ruiz; Frank D Petruzella; Denny D Watson; David K Glover
- Publisher
- Springer
- Year
- 2003
- Tongue
- English
- Weight
- 195 KB
- Volume
- 10
- Category
- Article
- ISSN
- 1071-3581
No coin nor oath required. For personal study only.
✦ Synopsis
Background:
We sought to determine whether a dual-isotope imaging strategy (rest thallium 201/stress technetium 99m sestamibi) might be useful for assessing myocardial viability and residual ischemia in the infarct zone very early after reperfusion.
Methods and results:
Fifteen open-chest dogs had left anterior descending coronary artery occlusion for 60 minutes, followed by full reperfusion (group 1, n = 8) or reperfusion through a residual critical stenosis (group 2, n = 7). tl-201 was injected at rest 45 minutes after reperfusion, and initial and 2-hour redistribution images were acquired. tc-99m sestamibi was then injected during vasodilator stress, followed by imaging. infarct size was similar in both groups (risk area, 21% +/- 4% vs 22% +/- 3%). rest tl-201 defect count ratios (left anterior descending coronary artery/left circumflex artery) were comparable (0.71 +/- 0.03 vs 0.74 +/- 0.02) and reflected infarct size. with vasodilation, tc-99m sestamibi defect count ratio in group 1 (0.71 +/- 0.02) was comparable to rest tl-201 and was significantly greater than in group 2 (0.62 +/- 0.02) with residual stenoses (p <.01). although vasodilator tc-99m sestamibi imaging unmasked the presence of residual stenoses, tc-99m sestamibi uptake underestimated their functional severity (flow ratio, 0.38 +/- 0.03).
Conclusions:
Dual-isotope imaging very early after reperfusion may have limited utility for detecting residual stenoses in the infarct zone. underestimation of the flow disparity by tc-99m sestamibi may make the detection of stenoses more difficult, and impaired flow reserve after ischemic insult may complicate the detection of fully reperfused segments.