Detection of myocardial viability in ischemic-reperfused rat hearts by Tc-99m sestamibi kinetics.
BACKGROUND
The purpose of this study was to evaluate technetium 99m sestamibi (MIBI) kinetics in assessing myocardial viability in hearts subjected to different ischemia-reperfusion treatments, resulting in graded severity of injury.


RESULTS
Sixteen isolated Krebs-Henseleit-perfused rat hearts were divided into 3 groups: control (flow, 12 mL/min; n = 5), ischemic-reperfused with glucose (IR+G, n = 6), and ischemic-reperfused without glucose (IR-G, n = 5). MIBI (11.1 mBq [300 microCi]) was infused for 60 minutes (uptake), followed by a 60-minute clearance. MIBI uptake (percent injected dose per gram) was significantly decreased in the IR+G (2.07 +/- 0.31) and IR-G groups (2.03 +/- 0.23; P = not significant with IR+G) compared with the control group (3.06 +/- 0.25, P <.05). Fractional washout of MIBI was more rapid in the IR-G group (72.7% +/- 3.9%, P <.05) than in the control (21.9% +/- 1.9%) and IR+G groups (20.3% +/- 1.7%). End retention (percent injected dose per gram) of MIBI in the IR-G (0.60 +/- 0.12) and IR+G groups (1.60 +/- 0.18) was significantly less than in the control group (2.30 +/- 0.11, P <.05), respectively. The retention in the IR-G group was less than in the IR+G group (P <.05). Creatine kinase assay, triphenyltetrazolium chloride staining, and transmission electron microscopy analysis demonstrated more serious myocardial damage in the IR-G group than in the IR+G group. End MIBI activity was highly correlated with myocardial viability determined by triphenyltetrazolium chloride staining (r = 0.94; P <.05) and creatine kinase assay (r = -0.86; P <.05).


CONCLUSIONS
Clearance of Tc-99m sestamibi is sensitive to metabolic states and may be used for assessment of ongoing myocardial damage.
Liu
Z
Z
William K. Warren Medical Research Institute of the University of Oklahoma Health Sciences Center, Tulsa , USA. zliu@u.arizona.edu
Johnson
G
G
Beju
D
D
Okada
R D
RD
D000818:Animals; D004396:Coloring Agents; D003402:Creatine Kinase / Q000097:blood; D004195:Disease Models, Animal; D006321:Heart / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006439:Hemodynamics / Q000502:physiology; D008297:Male; D008657:Metabolic Clearance Rate / Q000502:physiology; D008854:Microscopy, Electron; D017202:Myocardial Ischemia / Q000097:blood / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015428:Myocardial Reperfusion Injury / Q000097:blood / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D009206:Myocardium / Q000473:pathology* / Q000648:ultrastructure*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics*; D013778:Tetrazolium Salts; D013997:Time Factors
D004396:Coloring Agents; D019275:Radiopharmaceuticals; D013778:Tetrazolium Salts; C009591:triphenyltetrazolium; D017256:Technetium Tc 99m Sestamibi; D003402:Creatine Kinase