title: Comparison of myocardial perfusion imaging with technetium-99m tetrofosmin versus thallium-201 in coronary artery disease.
abstract: Technetium-99m (Tc-99m) tetrofosmin, a new myocardial perfusion imaging agent, was evaluated at exercise and rest in 50 patients with documented coronary artery disease to determine myocardial kinetics, redistribution and ideal imaging time. Planar imaging was performed at 5, 30, 60, 90, 120 and 240 minutes after an injection of Tc-99m tetrofosmin (8 to 10 mCi) at peak graded ergometric exercise. Reinjection (24 to 30 mCi) was performed at rest, 4 hours after the stress injection and also on a separate day, and imaging was repeated. All patients underwent thallium-201 (Tl-201) exercise and redistribution (4-hour) imaging. Perfusion defect to normal, and heart to lung ratios were calculated for exercise Tc-99m tetrofosmin images at each time point. The mean +/- SD defect to normal ratios were 0.75 +/- 0.10, 0.75 +/- 0.10, 0.74 +/- 0.09, 0.73 +/- 0.10, 0.73 +/- 0.10 and 0.72 +/- 0.10 at 5, 30, 60, 90, 120 and 240 minutes, respectively (p = NS), suggesting absence of redistribution. There was a significant increase in lung uptake of Tl-201 during exercise (p < 0.05), but not with Tc-99m tetrofosmin (p = NS). Washout of Tc-99m tetrofosmin was calculated in a subset of patients (n = 23). Rapid background clearance enabled postexercise diagnostic imaging as early as 5 minutes after injection. Myocardial retention curves after rest injection suggested that the optimal time for imaging was approximately 30 minutes later. Slow myocardial washout (4%/hour after exercise and 0.6%/hour after rest injection) enabled diagnostic images to be obtained up to 4 hours after each study.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Northwick Park Hospital, Harrow, United Kingdom.
authors.forename: B S
authors.initials: BS
authors.lastname: Sridhara
authors.forename: S
authors.initials: S
authors.lastname: Braat
authors.forename: P
authors.initials: P
authors.lastname: Rigo
authors.forename: R
authors.initials: R
authors.lastname: Itti
authors.forename: P
authors.initials: P
authors.lastname: Cload
authors.forename: A
authors.initials: A
authors.lastname: Lahiri
mesh_terms: D000368:Aged; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000378:metabolism; D005069:Evaluation Studies as Topic; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008168:Lung / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000493:pharmacokinetics; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D011877:Radionuclide Imaging; D013794:Thallium Radioisotopes / Q000493:pharmacokinetics
chemical_list: D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D013794:Thallium Radioisotopes; C078700:technetium tc-99m tetrofosmin