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Discordance between accumulation of C-14 deoxyglucose and Tl-201 in reperfused myocardium
L Sebree1, J A Bianco, R Subramanian
1Department of Radiology, University of Wisconsin Hospital and Clinics, Madison 53792.
Insights
Radiolabeled deoxyglucose (FDG) is not a reliable marker for detecting viable heart muscle after acute myocardial infarction. Studies show FDG uptake does not correlate with necrosis, questioning its use in reperfused myocardium.
Area of Science:
- Cardiovascular imaging
- Nuclear cardiology
- Myocardial viability assessment
Background:
- Radiolabeled deoxyglucose (FDG) has been proposed as a marker for assessing the viability of reperfused myocardium during acute myocardial infarction.
- However, limited data exist to support this recommendation.
Purpose of the Study:
- To investigate the cardiac deposition of C-14 deoxyglucose (C-14 DG) and Thallium-201 (Tl-201) in rabbits following coronary occlusion and reperfusion.
- To correlate myocardial concentrations of C-14 DG and Tl-201 with histological evidence of myocardial necrosis.
Main Methods:
- Rabbits underwent coronary occlusion for varying durations (15-100+ minutes) followed by reperfusion (75 minutes and 24 hours).
- Myocardial concentrations of C-14 DG and Tl-201 were measured using macroautoradiography.
- Quantitative correlation was performed between tracer deposition and myocardial necrosis evaluated by light microscopy.
Main Results:
- In regions with significant hypoperfusion (Tl-201) and necrosis after 30-60 minutes of ischemia and reperfusion, C-14 DG deposition did not correlate with necrosis (r=0.27).
- C-14 DG deposition was higher than Tl-201 deposition in acute myocardial infarction.
- Myocardial C-14 DG accumulation exceeded perfusion in the area-at-risk, regardless of occlusion time or early reperfusion.
Conclusions:
- These findings do not support the use of radiolabeled deoxyglucose for detecting myocardial viability in recently infarcted cardiac muscle.
- Thallium-201, despite variability, showed a more consistent relationship with perfusion deficits than C-14 DG.
Abstract:
Radiolabeled deoxyglucose (FDG) has been advocated as a marker of viability of reperfused myocardium during acute infarction. However, data for such recommendation are few. We investigated cardiac deposition of C-14 deoxyglucose (C-14 DG) and of Thallium -201 (Tl-201) in rabbits subjected to coronary occlusion (15, 30, 60 or greater than 100 min) and reperfusion (75 min and 24 h). Measured myocardial concentrations of C-14 DG and Tl-201 in macroautoradiograms were quantitatively correlated in a 24 h reperfusion group with presence of myocardial necrosis evaluated by light microscopy. The major finding in this investigation was that with 30 min or 60 min of ischemia followed by reperfusion there were myocardial regions with significant hypoperfusion (Tl-201) and histologic necrosis. However, in the same myocardial areas, the deposition of C-14 DG was not correlated with the extent of necrosis (r = 0.27). Also, the deposition of C-14 DG in acute myocardial infarction was higher than that of Tl-201 (P = 0.05 by paired T test and by nonparametric Wilcoxon's test). It was also demonstrated that when the occlusion time was varied (15-130 min) and early reperfusion was provided for 75 min or omitted altogether, the myocardial accumulation of Tl-201 was variable and that myocardial sequestration of C-14 DG was higher than perfusion in central and peripheral portions of the area-at-risk. These observations do not support a role for the use of radiolabeled deoxyglucose for the detection of myocardial viability in recently infarcted cardiac muscle.