[Quantitative evaluation of serial 201Tl Myocardial scintigrams after stress testing in ischemic heart disease...

Five normal adults and 31 patients with ischemic heart disease were studied by stress test, and 201Tl was injected one min. before the end of the test. Myocardial scintigrams in three views were recorded at 10 min, 1 and 2 hours (phase 0, 1 and 2) after the injection. The myocardial wall was geometrically divided into 5 segments. At the area where the count rate (Cts) was highest in phase 0 scintigrams, the washout rate from phase i to j was defined as WRij = (maxCtsi-maxCtsj)/maxCtsi where Ctsi denoted Cts at phase i in the relevant area. The redistribution index (Rdsij) in each segment was defined as Rdsij = [Ctsi X WRij + (Ctsi - Ctsj)]/Ctsi, where Ctsi denoted Cts at phase i in the segment. The ischemic segment was identified as 70% or less of maxCts 0, while the infarcted segment by VCG in phase 0 scintigram. Mean values of Rds 02 in the normal, ischemic and infarcted segments were -6.1 +/- 5.6, 9.7 +/- 7.0 and 3.5 +/- 7.2%, respectively, and the differences were statistically significant (p less than 0.001). All the 26 patients with anginal except one showed WR 12/WR 01 greater than 1.0. When the peak pressure rate product that attained at the test was 200 or more, it was significantly correlated with WR 02 (r = 0.80). The Redistribution index was helpful in quantitative assessment of the ischemic segments. The finding of WR 12 greater than WR 01 after the stress was reliable in suggesting myocardial ischemia.