Relationship between Tl-201, Tc-99m (Sn) pyrophosphate and F-18 2-deoxyglucose uptake in ischemically injured dog myocardium.
We have previously demonstrated that enhanced glucose utilization in reperfused myocardium as assessed by F-18 2-deoxyglucose (FDG) and positron tomography predicts functional recovery. In this study, we compared segmental uptake of F-18 FDG with that of Tl-201 and Tc-99m (Sn) pyrophosphate (Tc-99m PPi) as conventional markers of tissue viability in seven dogs after a 3-hour intracoronary balloon occlusion and 20 hours of reperfusion. Myocardial blood flow was determined with microspheres. Regional retention fractions were calculated from tracer tissue concentrations, the arterial input function, and blood flow. Ischemic injury was assessed by triphenyltetrazolium chloride (TTC) staining and histologic analysis. At 24 hours, blood flow was 22% lower in reperfused than in control myocardium (p less than 0.05). Uptake of Tl-201 was related linearly to blood flow (r = 0.92), while glucose utilization and Tc-99m PPi were 2.9 (p less than 0.01) and 4.7 (p less than 0.05) times higher in reperfused than in control myocardium. Retention fractions of Tc-99m PPi increased with the degree of ischemic injury, while F-18 FDG uptake was highest in segments with mild cell injury. Thus, in ischemically injured myocardium, Tl-201 primarily reflects blood flow. F-18 FDG as a marker of glucose utilization identifies ischemically injured but viable tissue. The admixture of necrotic cells can be determined with Tc-99m PPi. Our results indicate that a dual tracer approach might best characterize the presence and extent of reversibly and of irreversibly injured tissue in a given myocardial region.
Sochor
H
H
Department of Radiological Sciences, UCLA School of Medicine 90024.
Schwaiger
M
M
Schelbert
H R
HR
Huang
S C
SC
Ellison
D
D
Hansen
H
H
Selin
C
C
Parodi
O
O
Phelps
M E
ME
D000818:Animals; D003326:Coronary Circulation; D003327:Coronary Disease / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D003837:Deoxy Sugars; D003847:Deoxyglucose / Q000493:pharmacokinetics; D004285:Dogs; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D006321:Heart / Q000503:physiopathology; D006439:Hemodynamics; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D009336:Necrosis; D011122:Polyphosphates; D013667:Technetium / Q000493:pharmacokinetics; D016698:Technetium Tc 99m Pyrophosphate; D013794:Thallium Radioisotopes / Q000493:pharmacokinetics; D014003:Tin Polyphosphates / Q000493:pharmacokinetics
D003837:Deoxy Sugars; D005462:Fluorine Radioisotopes; D011122:Polyphosphates; D013794:Thallium Radioisotopes; D014003:Tin Polyphosphates; C017742:technetium Tc 99m stannous pyrophosphate; D016698:Technetium Tc 99m Pyrophosphate; D013667:Technetium; D003847:Deoxyglucose