This prospective study in 42 patients with chronic coronary artery disease and severe wall motion abnormalities (sWMA) on cineventriculography (24 patients with previous myocardial infarction; ejection fraction, 45% +/- 13%) was designed to compare myocardial thallium-201 uptake after rest injection and normalized fluorodeoxyglucose (18FDG) uptake (after oral glucose load) for assessment of a rest 201Tl protocol to evaluate myocardial viability. The left ventricle was divided into the supply territory of the left anterior descending coronary artery (LAD) and the lateral wall and posterior territory (inferior, posterior and posteroseptal segments) because of the high variability of left circumflex and right coronary artery supply territories. Segmental 201Tl uptake in single-photon emission tomography (SPET) and segmental normalized 18FDG uptake (13 segments per patient) showed a close linear relationship in the LAD territory (r = 0.79) and in the lateral wall (r = 0.77), while the correlation in the posterior territory was considerably lower (r = 0.52). 201Tl/18FDG concordance was defined as an 18FDG uptake exceeding 201Tl uptake by < 20%. Discordance was assumed if 18FDG exceeded 201Tl uptake by at least 20%. Concordant results were shown by 81% (439/541) of segments. In segments with severe 201Tl reduction (< or = 50% of peak, n = 78) discordance was observed in 10% of segments in the LAD territory and lateral wall (n = 62) and in 44% of segments in the posterior territory (n = 16).(ABSTRACT TRUNCATED AT 250 WORDS)