Clinical estimation of infarct size by 201thallium perfusion scintigraphy and by creatine kinase-MB in early myocardial infarction.

201Thallium (201Tl) perfusion scintigraphy was performed in 22 patients with first acute transmural myocardial infarction within the initial 12 h after onset of symptoms. The size of the abnormally perfused area on 201Tl images was estimated by visual analysis and by a computer-assisted technique. 201Tl values for infarct size were compared to a biochemical estimate of infarct size using the cardiac specific esoenzyme creatine kinase-MB (CK-MB) and total creatine kinase (CK). Estimates of myocardial damage obtained from the visual and computer-assisted analysis of the 201Tl images showed a statistically significant correlation with the enzymatic estimates of infarct size. These results suggest that quantitative evaluation of 201Tl image defects may provide useful information regarding the degree of myocardial damage in the very early stages of acute infarction before biochemical estimates of infarct size are available, and that sequential imaging with 201Tl might provide an independent method of monitoring evolutionary changes in myocardial damage.