Correlation between quantitative severity of stress thallium-201 myocardial perfusion defect and severity of coronary...

The correlation between the quantitative myocardial perfusion defect severity of stress 201Tl single-photon emission computed tomography and the severity of coronary stenosis was investigated in 28 patients with angina pectoris. Among the 28 patients, four had normal or nearly normal coronary angiograms, seven had one-vessel disease, six had two-vessel disease and 11 had three-vessel disease. Seven patients had prior myocardial infarctions and two had collateral flows to the diseased vessels. The quantitative 201Tl defect severity score was obtained by summing the standard deviations of each pixel in which the counts fell > 2.5 SD below the mean normal counts. The severity of coronary stenosis was expressed as the Gensini score. The quantitative 201Tl defect severity score correlated significantly with the Gensini score. In patients without prior myocardial infarction or collateral flow, a more significant correlation between the quantitative 201Tl defect severity score and the Gensini score was found. Quantitative analysis of stress 201Tl defect severity provides a useful, noninvasive assessment of the functional severity of coronary stenosis compared with coronary angiography.