Comparison of reinjection thallium 201 and resting technetium 99m sestamibi tomographic images for the quantification of infarct size after acute myocardial infarction
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Both thallium 201 and technetium 99m sestamibi have been used to quantitate infarct size at rest. Exercise201Tl scintigraphy has been shown to have powerful prognostic information after myocardial infarction. A single study using these agents that could provide data on infarct size and prognosis would be of value. The purpose of this study was to compare estimates of infarct size by use of201Tl and99mTc sestamibi and to correlate these measurements with left ventricular ejection fraction in patients after acute myocardial infarction.
Methods and Results
The study group consisted of 20 patients who underwent low-level201Tl stress studies with reinjection and99mTc sestamibi resting studies within 4 days. Acute reperfusion was attempted in 18 of 20 patients. For99mTc sestamibi tomographic imaging, infarct size was quantitated with 60% of maximal counts per slice for five short-axis slices as described in multiple previous studies. The postreinjection delayed201Tl images acquired 4 hours after stress were quantitated according to the same threshold method.201Tl patient images were also quantitated with a commercially available polar map program and compared with sex-matched control subjects. Ejection fraction was determined for each patient by radionuclide ventriculography 6 weeks later. Ejection fraction was well preserved for the group: mean 0.53±0.10. Infarct size with99mTc sestamibi was 12%±13% of the left ventricle, which was significantly smaller than either method with201Tl: threshold method, 29%±18% of left ventricle; polar map method, 25%±17% of left ventricle (both201Tl estimates,p<0.0001 vs99mTc sestamibi;201Tl, 70% threshold vs201Tl polar map,p=0.04). There was a significant correlation between infarct size with99mTc sestamibi and that with201Tl (r=0.72 to 0.73;p<0.001). Infarct size with99mTc sestamibi, however, provided the closest correlation with ejection fraction (r=0.81;p<0.001), with the two201Tl quantitative methods providing very similar correlations (r=0.69;p<0.001).
Infarct size with reinjection201Tl imaging correlates significantly with resting infarct size with99mTc sestamibi, although it provides significantly larger estimates. Although both approaches can be combined with a same-day exercise protocol, the closer correlation of infarct size with ejection fraction at 6 weeks suggests that resting infarct size with99mTc sestamibi may be slightly more accurate.
Key Wordsradionuclide imaging myocardial infarction radioistopes
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- 1.The TIMI Study Group. Comparison of invasive and conservative strategies after treatment with intravenous tissue plasminogen activator in acute myocardial infarction. N Engl J Med 1989;320:618–27.Google Scholar
- 7.Christian TF, Behrenbeck T, Pellikka PA, Huber KC, Chesebro JH, Gibbons RJ. Mismatch of left ventricular function and infarct size demonstrated by technetium-99m isonitrile imaging after reperfusion therapy for acute myocardial infarction: identification of myocardial stunning and hyperkinesia. J Am Coll Cardiol 1990;16:1632–8.PubMedGoogle Scholar
- 9.Perrone Filardi P, Dilsizian V, Maurea S, et al. Rest-redistribution thallium scintigraphy for identifying viable myocardium: relation to regional function and metabolic activity [Abstract]. Circulation 1991;84:1888.Google Scholar
- 10.Bonow RO, Dilsizian V, Cuocolo A, Bacharach SL. Identification of viable myocardium in patients with chronic coronary artery disease and left ventricular dysfunction: comparison of thallium scintigraphy with reinjection and PET imaging with18F-fluorodeoxyglucose. Circulation 1991;83:26–37.PubMedGoogle Scholar
- 20.The TIMI Study Group. The Thrombolysis in Myocardial Infarction Trial. N Engl J Med 1985;312:932–6.Google Scholar
- 25.Callahan RJ, Frolich HW, McKusick KA, Leppo J, Strauss HW. A modified method for the in vivo labelling of red blood cells with Tc-99m: concise communication. J Nucl Med 1981;23:315–8.Google Scholar
- 27.The Multicenter Postinfarction Research Group. Risk stratification and survival after myocardial infarction. N Engl J Med 1983;309:331–6.Google Scholar
- 39.DeCoster PM, Wijns W, Cauwe F, Robert A, Beckers C, Melin JA. Area-at-risk determination by technetium-99m-hexakis-2-methoxyisobutyl-isonitrile in experimental reperfused myocardial infarction. Circulation 1990;82:2151–62.Google Scholar
- 40.Medrano R, Weilbaecher D, Young JB, et al. Assessment of myocardial viability with technetium-99m-sestamibi in patients undergoing cardiac transplantation: a scintigraphic-pathologic study [Abstract]. Circulation 1992;86I:108.Google Scholar
- 44.Narahara KA, Villanueva-Meyer J, Thompson CJ, Brizendine M, Mena I. Comparison of thallium-201 and technetium-99m-hexakis-2-methoxyisobutyl-insonitrile single photon emission computed tomography for estimating the extent of myocardial ischemia and infarction in coronary artery disease. Am J Cardiol 1990;66:1438–44.PubMedCrossRefGoogle Scholar