Reproducibility of thallium 201 myocardial imaging

Abstract

Seventy six thallium 201 myocardial perfusion studies were performed on 25 patients to assess their reproducibility and the effect of varying the level of exercise on the results of imaging. Each patient had a thallium 201 study at rest. Fourteen patients had studies on 2 occasions at maximum exercise, and 12 patients had studies both at light and at maximum exercise. Of 70 segments in the 14 patients assessed on each of 2 maximum exercise tests, 64 (91%) were reproducible. Only 53% (16/30) of the ischemic defects present at maximum exercise were seen in the light exercise study in the 12 patients assessed at 2 levels of exercise. Correlation of perfusion defects with arteriographically proven significant coronary stenosis was good for the left anterior descending and right coronary arteries, but not as good for circumflex artery disease. Thallium 201 myocardial imaging at maximum exercise is reproducible within acceptable limits, but careful attention to exercise technique is essential for valid comparative studies.