The purpose of this study was to compare the incremental value of clinical information, electrocardiographic data, myocardial perfusion imaging, and radionuclide angiography for predicting severe coronary artery disease at a single testing interval. Photon attenuation is a major cause of artifacts on single-photon emission tomographic imaging. This new AC method provided an improved estimation of actual myocardial count activity. Even small defects with mild reduction in tracer activity were still identifiable after AC.
Clinical information, treadmill exercise studies, radionuclide angiography, and myocardial perfusion imaging are important predictors of severe coronary artery disease. Resting ischemia caused by moderate to severe stenosis can be detected on scans with (99m)TcN-NOET. Redistribution was near complete in this model by 90 to 120 minutes.
However, the relative and absolute diagnostic importance of each of these methods has not been addressed at a single testing interval. (99m)TcN-NOET is a promising new agent for the detection of coronary artery disease in viable myocardium and warrants further investigation. Negative charge-modified antibodies carry high specific radioactivity to the target sites without significantly increasing the background activity. Therefore we investigated whether higher dosages of negative charge-modified antibody can be used to improve imaging of experimental atherosclerotic lesions.
These data demonstrate that combined studies of myocardial perfusion and left ventricular function are able to improve prediction of the extent of coronary artery disease, even when clinical and electrocardiographic data are also available. The study demonstrated that the increase in the dosage of negatively charge-modified antibody allows a very high delivery of specific radioactivity to the target, which in turn enables early visualization of experimental atherosclerotic lesions.
However, the prognostic value of defects that become reversible after reinjection is not known. The presence of defects at stress-redistribution thallium-201 scintigraphy is related to a higher risk of cardiac events. Arbutamine stress single-photon emission computed tomographic imaging and echocardiography provide largely equivalent and accurate pathophysiologic information for the evaluation of coronary artery disease and inducible ischemia.
In this study we evaluated the prognostic contribution of stress-redistribution-reinjection with special regard to 3-hour fixed defects that become reversible after reinjection. (201)Tl reinjection is a useful approach for not only detecting viable myocardium but also risk stratification in patients with chronic myocardial infarction.
Arbutamine is a new synthetic catecholamine developed specifically for pharmacologic stress testing. High dosages of monoclonal antibody have been reported to be more efficacious in visualization of tumors. A family of integral cell membrane proteoglycans termed syndecans has recently been recognized. Among syndecans, syndecan-1, the first isolated member, has received most research attention.
Two factors that directly affect target/background ratio in immunoscintigraphy are the concentration of the antibody bound to the target and the concentration of the antibody in the circulation. Although administration of a higher dosage of antibody increases the absolute target accumulation of the radiotracer, it also increases the background activity, which may offset this advantage.
Enrichment of proteoglycans is prominent in early atherogenesis, contributing not only to SMC migration and proliferation, but also to low density lipoprotein retention. In this study, we examined the expression of syndecan-1 in rabbit aorta and aortic neointima, developed in response to a balloon catheter-induced de-endothelialization.
The tissues were processed for Northern blot analysis, in situ hybridization, immunohistochemical staining and immunoblotting. Our results indicate that in normal aorta, the signal for syndecan-1 is weak. However, arterial injury induces syndecan-1 expression at both mRNA and protein levels. The presence of syndecan-1 in the neointimal tissue is persistent, prominent even at the 12th week after injury. Syndecan positive cells are distributed in the whole layer of the neointima, but are not visible in the underlying media.