Myocardial viability assessment with technetium-99m-tetrofosmin and thallium-201 reinjection in coronary artery disease.

TLDR

Both 99mTc‑tetrofosmin and 201Tl can provide comparable information on myocardial viability through quantitative defect severity analysis. The study compared a 2‑day exercise‑rest 99mTc‑tetrofosmin protocol with exercise‑redistribution‑reinjection 201Tl imaging to evaluate 99mTc‑tetrofosmin’s ability to detect viable myocardium in 25 coronary artery disease patients with ventricular dysfunction. Patients underwent 99mTc‑tetrofosmin SPECT at 10 min during exercise and at 1 and 3 hr after rest, and within a week received 201Tl SPECT with exercise‑redistribution‑reinjection for visual defect reversibility assessment. Concordance between the two modalities was 60 % of segments, while 40 % were discordant; in 88 % of discordant segments 99mTc‑tetrofosmin showed nonreversible defects that were reversible on 201Tl, indicating that 99mTc‑tetrofosmin underestimates viability, though severity‑based analysis can improve detection.

Abstract

Exercise-rest 99mTc-tetrofosmin myocardial perfusion images with a 2-day protocol was compared to exercise-redistribution-reinjection 201Tl images to assess the ability of 99mTc-tetrofosmin to detect viable myocardium.We studied 25 patients with coronary artery disease and regional or global left ventricular dysfunction. Myocardial SPECT images with 99mTc-tetrofosmin were obtained 10 min after injection during exercise and 1 and 3 hr after rest injection. Within 1 wk of the 99mTc-tetrofosmin study, exercise-redistribution-reinjection 201Tl SPECT imaging was performed.Visual analysis demonstrated concordance between 201Tl and 99mTc-tetrofosmin imaging for defect reversibility in 126 of 209 segments (60%), with initial defects on both exercise 201Tl and 99mTc-tetrofosmin images. In the remaining discordant 83 segments (40%), 73 (88%) appeared nonreversible on 99mTc-tetrofosmin imaging but were reversible on 201Tl imaging.On the basis of defect reversibility by visual analysis, exercise-rest 99mTc-tetrofosmin imaging underestimates myocardial viability compared to 201Tl reinjection imaging. The identification of viable myocardium with both 99mTc-tetrofosmin and 201Tl can be greatly enhanced to a similar degree if the severity of reduction in activity within nonreversible defects is considered. These two agents may provide comparable information about myocardial viability by quantitative analysis of defect severity.