RESUMO
Technetium-99m (TC-99m)-teboroxime is a new myocardial perfusion imaging agent. The purpose of this prospective study was to compare Tc-99m-teboroxime with thallium-201 imaging after the administration of dipyridamole. Thirty patients referred for the evaluation of chest pain were studied with both thallium-201 and Tc-99m-teboroxime dipyridamole scans (mean interval 2 days). Dipyridamole was administered at 0.142 mg/kg/min for 4 minutes. Planar imaging (3 standard views) was obtained at 5 and 240 minutes after the injection of 2.2 mCi of thallium-201. Tc-99m-teboroxime (18 to 25 mCi) was injected after dipyridamole infusion. A second injection, at rest, was repeated 4 hours later. Planar imaging (3 standard views of 1 minute/view for the first 2 views, and 90 seconds for the last view) was obtained 2 minutes after Tc-99m-teboroxime injection. Blinded reading was performed by 3 observers. Thallium-201 showed perfusion defects in 182 myocardial segments corresponding to 33 of 45 (73%) significantly stenosed coronary arteries (greater than or equal to 70% reduction in endoluminal diameter), and Tc-99m-teboroxime detected 160 abnormal segments corresponding to 29 of 45 (64%) stenosed arteries. Thallium-201 and Tc-99m-teboroxime studies were normal in 3 patients. In conclusion, this study shows that there is a good correlation in the imaging results found with thallium-201 and Tc-99m-teboroxime using dipyridamole infusion on both a segmental and a diagnostic comparison.
Assuntos
Doença das Coronárias/diagnóstico por imagem , Compostos de Organotecnécio , Oximas , Radioisótopos de Tálio , Adulto , Idoso , Idoso de 80 Anos ou mais , Dipiridamol , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Radiografia , CintilografiaRESUMO
A total of 372 consecutive dipyridamole-thallium studies were reviewed to determine if a relationship existed between the dose of dipyridamole administered and the likelihood that thallium images would show reversible defects. Men who received a dose of less than 31 mg were less likely to have thallium redistribution (P = 0.0001). Until the ideal study involving repeat testing with incremental dipyridamole doses on different days is carried out, the authors recommend that a minimal dose of 31 mg be administered for dipyridamole-thallium imaging.
