[Quantitative analysis of exercise 201Tl myocardial emission CT in patients with coronary artery disease]

Abstract

The clinical usefulness of quantitative analysis of exercise thallium-201 myocardial emission computed tomography (ECT) was evaluated in coronary artery disease (CAD). The subjects consisted of 20 CAD patients and five normal controls. All CAD patients underwent coronary angiography. Tomographic thallium-201 myocardial imaging was performed with a rotating gamma camera, and long-axial and short-axial myocardial images of the left ventricle were reconstructed. The tomographic images were interpreted quantitatively using circumferential profile analysis. Based on features of regional myocardial thallium-201 kinetics, two types of abnormalities were studied: diminished initial distribution (stress defect) and slow washout of thallium-201, as evidenced by patients' initial thallium-201 uptake and 3-hour washout rate profiles which fell below the normal limits, respectively. Two diagnostic criteria including the stress defect and a combination of the stress defect and slow washout were used to detect coronary artery lesions of significance (greater than or equal to 75% luminal narrowing). The ischemic volumes were also evaluated by quantitative analysis using thallium-201 ECT. The diagnostic accuracy of the stress defect criterion was 95% for left anterior descending, 90% for right, and 70% for left circumflex coronary artery lesions. The combined criteria of the stress defect and slow washout increased detection sensitivity with a moderate loss of specificity for identifying individual coronary artery lesion. A relatively high diagnostic accuracy was obtained using the stress defect criterion for multiple vessel disease (75%). Ischemic myocardial volume was significantly larger in triple vessel than in single vessel disease (p less than 0.05) using the combined criteria.(ABSTRACT TRUNCATED AT 250 WORDS)