Comparison of sestamibi, tetrofosmin, and Q12 retention in porcine myocardium.
Although there are several 99mTc perfusion tracers introduced for clinical use, there are no data available directly comparing these tracers with microsphere-determined flow. The aim of this study was to compare the myocardial retention of sestamibi, tetrofosmin, and Q12 in a porcine model.


METHODS
We used a pig model with (n = 6) or without (n = 3) coronary occlusion. Each pig received a simultaneous injection of sestamibi and either tetrofosmin (group 1, n = 5) or Q12 (group 2, n = 4) labeled with either 99mTc or 95mTc (physical half-life, 61 d; photon energy, 204 keV) during pharmacologic vasodilation. Absolute myocardial retention of each tracer was calculated from the myocardial tracer activity and arterial input function.


RESULTS
The plot of all three tracers versus flow achieved a plateau at a higher flow range. However, sestamibi showed a higher mean retention than either tetrofosmin (group 1, 0.27 +/- 0.11 vs. 0.16 +/- 0.06 mL/g/min, respectively; P < 0.01) or Q12 (group 2, 0.32 +/- 0.13 vs. 0.09 +/- 0.03 mL/g/min, respectively; P < 0.01). Furthermore, when a linear regression analysis was performed to assess the relationship between retention and microsphere-determined flow, sestamibi showed a greater increment in retention than did tetrofosmin or Q12.


CONCLUSIONS
Although all of the tracers showed a nonlinear increase in retention as flow increased, sestamibi may display more favorable characteristics as a flow tracer in the porcine heart.
Matsunari
I
I
Department of Nuclear Medicine, Technische Universität München, Klinikum rechts der Isar, Germany.
Haas
F
F
Nguyen
N T
NT
Reidel
G
G
Wolf
I
I
Senekowitsch-Schmidtke
R
R
Stöcklin
G
G
Schwaiger
M
M
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003326:Coronary Circulation; D004176:Dipyridamole / Q000494:pharmacology; D004280:Dobutamine / Q000494:pharmacology; D005663:Furans / Q000493:pharmacokinetics; D006321:Heart / Q000000981:diagnostic imaging* / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D016014:Linear Models; D009206:Myocardium / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000493:pharmacokinetics; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D013552:Swine; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics
D005663:Furans; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078496:technetium Tc 99m Q12; D004280:Dobutamine; C078700:technetium tc-99m tetrofosmin; D004176:Dipyridamole; D017256:Technetium Tc 99m Sestamibi