[Evaluation of patients with ischemic heart disease by exercise thallium-201 myocardial imaging: comparison with coronary arteriography and graded treadmill exercise testing].

One hundred and eight patients with suspected ischemic heart disease were evaluated by exercise thallium-201 myocardial imaging (T1-IM), coronary arteriography and graded treadmill exercise test (GTX). They were divided into four groups; Group I consisted of 21 patients without significant coronary artery disease (less than 75% diameter stenosis), Group II of 47 patients with significant coronary artery disease (greater than or equal to 75% diameter stenosis) but without previous myocardial infarction, Group III of 24 patients who had previous myocardial infarction with additional coronary artery disease, and Group IV of 16 patients who had previous myocardial infarction without additional coronary artery disease. In Group I, T1-IM showed positive findings in only two patients (9.5%), whereas GTX showed positive findings in seven (33.3%) and borderline findings in four (19.0%). In Group II, T1-IM showed positive findings in 34 patients (74.5%), while GTX showed positive findings in 31 (66.0%) and borderline findings in 12 (25.5%). In Group II, the sensitivity of T1-IM and GTX for identifying severe stenosis (more than 99%) were 95.0% (19 of 20 patients) and 75.0% (15 of 20), respectively, but only 50.0% (four of eight) and 50.0% (four of eight), respectively, for identifying less severe stenosis (about 75%). In Group III, the sensitivity for detecting infarcted lesion by T1-IM was 95.8% (23 of 24 patients), but the sensitivity for detecting ischemic area in the non-infarcted lesion was 41.7% (10 of 24). In Group IV, a significant defect was detected by TI-IM, corresponding to the infarcted site in 14 of 16 patients (87.5%), and periinfarcted ischemia was shown in seven of the 14 patients (50.0%). In both Group III and IV, GTX was positive in only 50% and 31.3%, respectively. We conclude that T1-IM is a useful technique in the diagnosis of myocardial ischemia, especially severe coronary stenosis, and is more specific than GTX. However, we must be careful for evaluating ischemic, but not infarcted lesion by T1-IM in patients with myocardial infarction.