[Clinical usefulness of the quantitative assessment of exercise thallium-201 myocardial imaging in patients with ischemic heart disease].

To clarify the significance of the quantitative analysis of the area of decreased activity in exercise thallium-201 myocardial imaging, 42 patients with one vessel disease (20 patients with angina pectoris without myocardial infarction, 22 patients with old myocardial infarction: MI) were evaluated by exercise thallium scan and compared with clinical findings and wall motion assessed by left ventriculography (LVG). Patients with MI were divided into two groups by LVG (Mild MI: MI with only hypokinesis on LVG, Severe MI: MI with akinesis or dyskinesis on LVG). The degree of defected area was expressed by the ratio of the counts of defected area to the normal area (Relative Activity: RA). RA of the area of decreased activity in patients with angina was higher than that of patients with MI (77.5 +/- 4.59% vs. 65.7 +/- 7.85%, p < 0.05). RA of the area of decreased activity in patients with mild MI was higher than that of patients with severe MI (69.5 +/- 4.78% vs. 61.3 +/- 8.45%, p < 0.01). The above results suggest that the regional thallium-201 uptake ratio in the scintigram may help to differentiate viable zones from necrotic ones and detect the degree of MI.