ECG gating of thallium-201 myocardial images: effect on detection of ischemic heart disease

Using the angiographic findings as the standard, we have examined the sensitivity and specificity of ECG-gated static thallium-201 myocardial images in 54 patients undergoing selective coronary arteriography. Gated and nongated images, each in anterior, 45 LAO, and 65 LAO projections, were processed by interpolative background subtraction. They were then analyzed separately by four independent observers who were unaware of patient identity, the results of coronary arteriography, and which studies were gated or nonongated. No significant differences were observed between the gated and ngated images regarding sensitivity or specificity, the detection rate for reversible myocardial ischmia, the accuracy of prediction of arteriographic extent of disease, or the degree of inter-or intraobserver variability. We conclude that ECG-gated acquisition of Tl-201 images does not produce any significant advantages, at least when interpolative background subtraction is used