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This Article Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Brennan, M. Articles by Sinusas, A. PubMed Articles by Brennan, M. Articles by Sinusas, A.

Optimization of 99mTc-Glucarate and 201Tl dual-isotope SPECT imaging for quantitative evaluation of acute myocardial infarction: Pre-clinical validation

¹ Medicine / Cardiology, Yale University School of Medicine, New Haven, Connecticut

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Objectives: Early detection and quantification of acute myocardial infarction (MI) is critical in evaluation of patients presenting with chest pain. We propose to compare simultaneous 99mTc-Glucarate (GL) and 201Tl (TL) dual isotope SPECT imaging with sequential imaging for the optimal early evaluation of acute myocardial infarction.

Methods: 5 dogs underwent 2h surgical LAD occlusion and complete reperfusion. GL (25+/-2.2mCi) [MTTI, West Chester, PA] was injected IV 1h after reflow. In vivo SPECT/CT [GE Infinia] was performed within 2-4h of GL injection. After single GL imaging, TL (2.0+/-0.4mCi, IV) was injected and dual-isotope SPECT/CT initiated 15m later. Hearts were excised and LV cut into axial slices (1cm), and 16 radial pies for gamma well counting (GWC). In vivo attenuation corrected GL SPECT/CT images before and after injection of TL were analyzed using quantitative software, and regional activity (% non-ischemic (NI)) were compared with GWC activity (%NI). MI extent defined by % pies with GWC activity <70% NI.

Results: Infarct extent was 20.8+/-10.2 %LV. TL activity within MI region was 57.7+/-11 %NI, while GL activity was 2212+/-2736 %NI (see figure). In vivo GL activity (%NI) was similar before and after TL injection (r=0.80). However, there was no relationship (r=0.23) in vivo between TL and GL, suggesting that there was significant downscatter of GL into TL window.

Conclusions: GL imaging is a sensitive marker of MI. Simultaneous GL and TL dual isotope SPECT/CT in vivo imaging is possible and provides a reliable quantitative index of GL activity. However, Tl perfusion can not be assessed after injection of GL, and must precede GL "hotspot" imaging secondary to spill down.

This Article Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Brennan, M. Articles by Sinusas, A. PubMed Articles by Brennan, M. Articles by Sinusas, A.