Specific perfusion pattern in stress 201Tl myocardial scintigraphy of left main coronary artery disease.

The usefulness of stress 201Tl myocardial scintigraphy for identifying left main coronary artery disease was evaluated with data from 23 patients with 50% or more narrowing of the left main coronary artery and 56 patients with 75% or more narrowing of the major coronary arteries but without left main coronary artery involvement (no left main coronary artery disease). Quantitative evaluation of stress perfusion scintigrams in all five patients with narrowing of the left main coronary artery of 90% or more showed a characteristic perfusion pattern (left main pattern) of extensive homogeneous defect over the whole anterolateral segment and simultaneous defects in all radii of the high anteroseptal and high posterolateral segments. On the other hand, such a perfusion pattern was noted in only 1 of 18 patients with less than 90% stenosis of the left main coronary artery and in only 1 of 56 patients with no left main coronary artery disease.