Demonstration of differential post-stenotic myocardial technetium-99m-teboroxime clearance kinetics after experimental ischemia and hyperemic stress.
The clearance kinetics of the perfusion tracer 99mTc-teboroxime were evaluated in post-stenotic and normal myocardium using dynamic planar gamma camera imaging in pre-instrumented dogs in the control state (n = 9) and following total occlusion (2 min), pharmacologic stress with adenosine [80 and 160 micrograms/kg/min] or dipyridamole, and rapid atrial pacing (220/min). Technetium-99m-teboroxime clearance in normal myocardium was accelerated by adenosine and by dipyridamole compared to the control state (8.9 +/- 1.1 and 9.3 +/- 1.9 min versus 11.9 +/- 1.8 min; p less than 0.05). Post-stenotic 99mTc-teboroxime clearance half-time was most significantly prolonged compared to nonoccluded contralateral perfusion zones by 160 micrograms/kg/min adenosine stress (11.2 +/- 3.7 versus 6.3 +/- 1.5 min) and by complete coronary occlusion (12.1 +/- 3.3 versus 6.6 +/- 1.2 min; both p less than 0.05). Differential tracer clearance from post-stenotic versus nonoccluded zones produced quantitative evidence of relative defect "redistribution" in 71% of maximal stress studies at a mean of 8.8 +/- 2.5 min postinjection. Sensitivity, specificity, and diagnostic accuracy of prolonged regional 99mTc-teboroxime clearance rates for post-stenotic perfusion abnormalities were 62%, 100% and 81% in maximal stress studies. Future clinical trials of exercise and nonexercise stress 99mTc-teboroxime imaging should consider these kinetic characteristics and examine the correlates of perfusion defect "redistribution."
Department of Medicine, University of Texas Health Science Center, San Antonio.
R E
RE
Stewart
B
B
Heyl
R A
RA
O'Rourke
R
R
Blumhardt
D D
DD
Miller
D000241:Adenosine; D000818:Animals; D002304:Cardiac Pacing, Artificial; D003326:Coronary Circulation / Q000502:physiology; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D004176:Dipyridamole; D004285:Dogs; D006321:Heart / Q000000981:diagnostic imaging*; D007091:Image Processing, Computer-Assisted; D009200:Myocardial Contraction / Q000502:physiology; D009206:Myocardium / Q000378:metabolism; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D010091:Oximes / Q000493:pharmacokinetics; D011877:Radionuclide Imaging
D015609:Organotechnetium Compounds; D010091:Oximes; D004176:Dipyridamole; D000241:Adenosine; C060156:technetium Tc 99m teboroxime