Improved detection of coronary artery disease by estimated myocardial thallium uptake (original) (raw)
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Slow late myocardial clearance of thallium: a characteristic phenomenon in coronary artery disease
Circulation, 1982
We extended the quantitative seven-pinhole method to follow the dynamics of thallium redistribution after exercise. We observed a pattern of slow late thallium clearance that appears to be characteristic of myocardium supplied by obstructed coronary arteries. In 28 subjects, quantitative thallium scintigrams (seven-pinhole tomography, circumferential count profiles) and blood samples for thallium concentration were taken immediately, 2 hours and 4 hours after maximal treadmill exercise. Twenty subjects had coronary artery disease (CAD) and eight were normal. The rate of thallium clearance from the blood (TCB) was compared with the rate of thallium clearance from each segmental region of myocardium (TCM, derived by ratioing corresponding segments of the absolute circumferential count profiles) between the 2- and 4-hour images. In seven of the eight normal subjects, TCM exceeded TCB in all regions of all images (specificity 88%). Seventeen of the 20 CAD patients had at least one regio...
Quantification of myocardial ischemia and infarction with 201 thallium scintigraphy
Clinical Cardiology, 1979
A quantitative method for the analysis of 'O'thallium myocardial scintigrams, developed in an experimental infarcted dog heart model, has been compared with two nonquantitative methods for interpretation of stress myocardial scintigrams in two groups of patients studied with coronary angiography: 1 1 with normal coronary arteries and I4 with coronary artery disease. Three independent observers interpreted scintigrams which were I ) not computer processed; 2) corrected for background activity in lungs and chest wall; and 3) processed by a computer method which uses a uniform threshold of counts determined from the dog model to define perfusion defects. lnterobserver variability as well as sensitivity and specificity of detecting coronary disease were examined.
International Journal of Cardiology, 1986
In this study the relative importance of visual assessment and quantitative analysis of myocardial stress perfusion scintigraphy in 72 patients with a 40% incidence of triple-vessel coronary disease was tested. The quantitative analysis of the uptake scintigram in combination with a washout rate study of thallium-201 was not superior to the visual analysis with regard to the overall detection of significant coronary disease (obstructions of at least 50%). The sensitivity of the quantitative analysis was 0.85 for the entire population and 0.90 for the triple-vessel disease group (specificity 0.90). Detection of jeopardized myocardial flow regions in patients with triple-vessel disease, however, resulted in a significantly better identification by quantitative analysis. Of the 87 jeopardized flow regions in the 29 patients with triple-vessel disease, 62 regions were detected by the quantitative analysis whereas 48 regions were noted by the visual evaluation. The post-test likelihood of this regional quantitative analysis with respect to the triple-vessel disease was 66%. The incidence of global ischemia as detected by washout abnormalities in cases with no or a maximum of one regional uptake defect was 7%.
European Journal of Nuclear Medicine, 1990
Quantitative analysis of myocardial exercise scintigraphy has been previously reported to be superior to visual image interpretation for detection of the presence and extent of coronary artery disease. Computer analysis of perfusion defects and washout rate of thallium 201 was performed on scintigrams from a group of 131 consecutive patients (prospective group), using criteria defined from a previous group of 72 patients (initial group), and compared with visual interpretation of scintigrams for detection and evaluation of coronary artery disease. The sensitivity of the quantitative technique with regard to overall detection of coronary artery disease was not significantly different from the visual method (69% and 74%, respectively), whereas the specificity was higher (86% and 68%). Quantitative analysis did not increase the sensitivity of thallium imaging over the visual method in the left anterior descending artery (46% vs 65%) and the right coronary artery (51% vs 72%) but did increase sensitivity in the left circumflex artery (75% vs 47%). Whereas in the initial group quantitative analysis resulted in a better identification of multivessel disease (sensitivity 81% vs 57%), in the prospective group sensitivity decreased (54% vs 67%) without significant loss of specificity. The initial group had a 40 % incidence of three-vessel disease and the prospective group, 22% (P<0.05). One-vessel disease was higher in the prospective group (32% vs 11%, P< 0.05). Thus, assessing the quantitative technique in a larger prospective patient population, there was no improvement of Offprint requests to." E.K.J. Pauwels detection of the presence and extent of coronary artery disease when compared with visual interpretation. Key words: Thallium 201 myocardial scintigraphy -Thallium 201 washout -Exercise test -Coronary artery disease Eur J Nucl Med (1990) 16:697-704
European Journal of Nuclear Medicine, 1987
This study compared the accuracy of rest and exercise gated equilibrium technetium ventriculography with exercise thallium imaging in 50 consecutive male patients undergoing routine coronary angiography for the evaluation of chest pain. No patients were excluded on the basis of prior myocardial infarction, nature of angiographically defined coronary disease or symptoms. Antianginal therapy was continued in all patients. Eight patients had normal coronary arteries, 9 had single vessel, disease, 20 had double vessel disease and 13 had triple vessel disease. Sixteen patients had previously documented myocardial infarction. Using exercise radionuclide ventriculography, 34 patients with coronary disease were detected resulting in a sensitivity of 81%; 6 patients with normal coronary arteries had normal scans, a specificity of 75%, with a predictive accuracy of 80%. In comparison, thallium imaging detected 42 patients with coronary disease resulting in a sensitivity of 100%. Six patients with normal coronary arteries had normal thallium images resulting in a specificity of 75% and a predictive accuracy of 96%. These results suggest that exercise thallium imaging is a more accurate investigation than exercise equilibrium radio-nuclide ventriculography and is the investigation of choice in the noninvasive detection of coronary artey disease.
Circulation, 1981
Visual interpretation of stress-redistribution thallium-201 (201T1) scintigrams is subject to observer variability and is suboptimal for evaluation of extent of coronary artery disease (CAD). An objective, computerized technique has been developed that quantitatively expresses the relative space-time myocardial distribution of 201TI. Multiple-view, maximum-count circumferential profiles for stress myocardial distribution of 201T1 and segmental percent washout were analyzed in a pilot group of 31 normal subjects and 20 patients with CAD to develop quantitative criteria for abnormality. Subsequently, quantitative analysis was applied prospectively to a group of 22 normal subjects and 45 CAD patients and compared with visual interpretation of scintigrams for detection and evaluation of CAD. The sensitivity and specificity of the quantitative technique (93% and 91%, respectively) were not significantly different from those of the visual method (91% and 86%). The quantitative analysis significantly (p < 0.05) increased the sensitivity of 20'Tl imaging over the visual method in the left anterior descending artery (from 56% to 80%), left circumflex artery (from 34% to 63%) and right coronary artery (from 65% to 94%) without significant loss of specificity. Using quantitative analysis, sensitivity for detection of diseased vessels did not diminish as the number of vessels involved increased, as it did with visual interpretation. In patients with one-vessel disease, 86% of the lesions were detected by both techniques; however, in patients with three-vessel disease, quantitative analysis detected 83% of the lesions, while the sensitivity was only 53% for the visual method. Seventy percent of the coronary arteries with moderate (50-75%) stenosis were detected quantitatively, compared with 35% by the visual method. We conclude that this quantitative technique for analysis of stress-redistribution 201T1 scintigrams is objective and more sensitive than the visual method, especially in patients with multiple-vessel disease and those with moderate coronary artery stenosis.
The American Journal of Cardiology, 1978
A multicenter study of rest and exercise thallium-201 myocardial imaging in 190 patients from five centers was performed. Exercise images were obtained after graded treadmill or bicycle stress with use of five different gamma camera models and were interpreted by the originating investigator without knowledge of other clinical data. Of 42 patients with less than 50 percent coronary stenosis, 4 (10 percent) had a resting image defect, 1 (2 percent) a new exercise defect and 5 (12 percent) either a resting or an exercise image defect, or both. Of 148 patients with coronary stenosis of 50 percent or greater, 64, (45 percent) had an image defect in the study at rest, 90 (61 percent) had new or increased defects after exercise, and 115 (78 percent) had resting or exercise defects, or both. New exercise image defects were more common than exercise S-T depression (90 of 148 [61 percent] versus 62 of 148[42 percent]; P less than 0.01). In a second group of 111 patients with acute myocardial infarction studied at three centers, 90 patients (81 percent) had image defects compared with 71 (64 percent) two had new electrocardiographic Q waves (P less than 0.01). Smaller infractions, as assessed with serum enzyme values, and diaphragmatic infarctions were less commonly detected than larger or anterior infarctions. These findings suggest that myocardial imaging complements the electrocardiographic identification of acute myocardial infarction of exericse-induced myocardial ischemia.