Quantitative evaluation of serial 201-Tl myocardial scintigrams after stress testing in ischemic heart disease

Eight normal adults and forty-two patients with ischemic heart disease were studied by stress testing. Myocardial scintigrams in three views (anterior, left anterior oblique and left lateral projectons) were obtained at ten minutes, one and two hours (phase 0,1 and 2) after the 201-T1 bolus injection. The myocardial wall was geometrically divided into five segments each view. The washout rate from phase i to j(WRij) was defined as WRij = (maxCtsi - maxCtsj) /maxCtsi where maxCtsi denoted maximal Cts at phase i in the relevant view. The washout rate 02 (WR02) showed the decreasing rate of the net rate of 201-T1 for two hours after the injection. The redistribution index (cRdsij) in each segment was defined as cRdsij = [Ctsi x WRij + (Ctsj - Ctsi)]/maxCtsi, where Ctsi denoted mean Cts at phase i in the segment. cRds02 showed the redistributed counts which were estimated by adding WR02 for two hours. ΣcRdsij denoted the sum of 15 cRdsij. MaxcRdsij indicated as the maximum of 15 cRdsij. RI angiography was also performed in the twenty-eight cases who had myocardial scintigram under stress testing. In conclusion, the redistribution index (cRds02) was helpful in quantitative assessment of the ischemic segments. And ΣcRds02 was also helpful in the evaluation of ischemic heart disease. The finding that WR12 was greater than WR01 after the stress was reliable in suggesting transient myocardial ischemia. The evaluation of ischemic heart disease using ΣcRds02 and EF was useful, in particular the evaluation of LV function in old myocardial infarction with angina and without angina. (J.P.N.)