[Left ventricular ejection fraction derived from resting 201Tl myocardial images].

To determine if resting 201Tl myocardial scintigraphy (rest-Tl) provides the information on left ventricular function, we compared preliminarily the parameters derived from rest-Tl with left ventricular ejection fraction (LVEF) derived from left ventriculography; while the parameters included Extent Score (ES), Severity Score (SS), Percent Uptake (PU), Area Index (AI). AI was derived from the averaging of [(A/B) x 100] in three or four central slices of short axis view on single photon emission computed tomography (A; area surrounded by inner edge of 201Tl myocardial image, B; area surrounded by outer edge of 201Tl myocardial image). The patients were comprised of 38 males and 16 females with a mean age of 53 years old (range 15-70) and classified into two groups; patients with myocardial infarction (n = 28, Group I), and patients with miscellaneous disease but without myocardial infarction (n = 26, Group II). In Group I, ES, SS and AI correlated with LVEF. If ES was less than 0.30, SS was less than 26.2, or AI was less than 19.8, LVEF was suggested more than 60% with an accuracy of 92%, 85% and 85%, respectively. In Group II, these did not correlate with LVEF. If there were area with PU less than 70% in the region perfused by left anterior descending artery or left circumflex artery, LVEF was less than 60% with an accuracy of 78%. In conclusion, rest-Tl images provide some informations on left ventricular function in some patients.