title: Arterial concentration of 99mTc-sestamibi at rest, during peak exercise and after dipyridamole infusion.
abstract: Tracers for myocardial perfusion imaging during stress should not only have high cardiac uptake but they should also have a fast blood clearance to prevent myocardial tracer uptake after the ischaemic stimulus. The present study characterize the early phase of the arterial (99m)Tc-sestamibi (MIBI) time-activity curve after venous bolus injection at rest, during peak exercise and after dipyridamole infusion. We included 11 patients undergoing angioplasty for one-vessel disease (rest study) and 20 patients evaluated for the detection of haemodynamic significant coronary stenoses by (99m)Tc-sestamibi single photon emission computed tomography (SPECT) using either bicycle exercise testing (10 patients) or standard dipyridamole testing (10 patients). Arterial blood samples of 1 ml were taken from the left femoral artery (rest study) or the right radial artery (exercise and dipyridamole studies) every 5 s during the first 5 min postinjection. In the exercise and the dipyridamole studies blood sampling were extended to include blood samples every 5 min 5-30 min postinjection. Peak MIBI concentration was lower and decrease in concentration slower after tracer injection during exercise than during dipyridamole stress testing. This may cause an underestimation of perfusion defects during exercise because of MIBI uptake after the ischaemic stimulus. The implications of the study not only refer to the choice of stress modality when using MIBI. This study also underlines the importance of considering early blood clearance in addition to regional myocardial tracerkinetic aspects such as myocardial extraction fraction when new tracers are introduced.
authors.affiliation: Department of Nuclear Medicine, Skejby Sygehus, Aarhus University Hospital, DK-8200, Aarhus N, Denmark.
authors.forename: Niels Peter Rønnow
authors.initials: NP
authors.lastname: Sand
authors.forename: Palle
authors.initials: P
authors.lastname: Juelsgaard
authors.forename: Karin
authors.initials: K
authors.lastname: Rasmussen
authors.forename: Christian
authors.initials: C
authors.lastname: Flø
authors.forename: Leif
authors.initials: L
authors.lastname: Thuesen
authors.forename: Jens Peder
authors.initials: JP
authors.lastname: Bagger
authors.forename: Torsten Toftegaard
authors.initials: TT
authors.lastname: Nielsen
authors.forename: Michael
authors.initials: M
authors.lastname: Rehling
mesh_terms: D001158:Arteries / Q000000981:diagnostic imaging / Q000378:metabolism; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000378:metabolism*; D004176:Dipyridamole / Q000008:administration & dosage*; D005080:Exercise Test / Q000379:methods*; D006801:Humans; D007261:Infusions, Intra-Arterial; D008657:Metabolic Clearance Rate; D019275:Radiopharmaceuticals / Q000097:blood / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012146:Rest; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi / Q000097:blood* / Q000493:pharmacokinetics; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
chemical_list: D019275:Radiopharmaceuticals; D004176:Dipyridamole; D017256:Technetium Tc 99m Sestamibi