A consideration of factors affecting the diagnostic accuracy of thallium-201 myocarial perfusion scintigraphy in detecting coronary artery disease.

Several factors influence the ability of TI-201 myocardial perfusion scintigraphy to detect coronary artery disease. Among these are the physiologic effect of the coronary lesion on relative myocardial perfusion and radionuclide distribution; technical and physiologic aspects of the scintigraphic process; and observer interpretation. The diagnostic accuracy of this scintigraphic method is related to: (1) the extent of the hypoperfused myocardium, which will depend on the severity and extent of coronary disease, the presence of collaterals, the exercise method, and the timing of thallium administration and scintigraphy; (2) the scintigraphic process, which depends on the nature of the isotope, the imaging system, and the method of image display; and (3) image interpretation, which depends on the experience of the observer as well as on the area of hypoperfused myocardium and the scintigraphic process. The diagnostic accuracy of scintigraphy for detecting coronary disease can be optimized by computer methods of image enhancement, which maximize differences in image contrast; by electrocardiographic gating; and by emission computer tomography. Other computer methods have been developed to reduce or eliminate observer intervention in interpretation and to increase the objectivity of the method.