Kinetics of a putative hypoxic tissue marker, technetium-99m-nitroimidazole (BMS181321), in normoxic, hypoxic, ischemic and stunned myocardium.
This study focused on the kinetics of the newly developed 99mTc-nitroimidazole, propyleneamine oxime-1,2-nitroimidazole (BMS181321) in the different setting of myocardial perfusion states and oxygenation levels, and compared the kinetics of BMS181321 with those of other technetium analogues.


METHODS
The kinetics of BMS181321 were evaluated in isolated perfused rat hearts. Technetium-99m-hexamethylpropyleneamine oxime (HMPAO) and a non-nitroimidazole-containing analogue of BMS181321 (6-methyl propyleneamine oxime; PAO-6-Me) were used to compare their kinetics with those of BMS181321.


RESULTS
BMS181321 cleared quickly from normoxic hearts and the retention in the myocardium 10 min after injection was 0.84% +/- 0.04% ID/g wet wt (mean +/- s.e.m.). In contrast, BMS181321 was retained after reperfusion when it was injected before ischemia; the uptake in the myocardium 10 min after reperfusion was significantly greater than in controls (23.9% +/- 3.9% ID/g wt, p < 0.05).


CONCLUSIONS
These results indicate that 99mTc-BMS181321 is well trapped in ischemic myocardium and moderately trapped in hypoxic myocardium, but washed out quickly in stunned myocardium. The residence time influences the amount retained.
Kusuoka
H
H
Division of Tracer Kinetics, Osaka University Medical School, Japan.
Hashimoto
K
K
Fukuchi
K
K
Nishimura
T
T
D000818:Animals; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging*; D017682:Myocardial Stunning / Q000000981:diagnostic imaging*; D009206:Myocardium / Q000378:metabolism; D009593:Nitroimidazoles / Q000493:pharmacokinetics; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D010091:Oximes; D010101:Oxygen Consumption / Q000502:physiology; D010477:Perfusion; D011877:Radionuclide Imaging; D051381:Rats; D019690:Technetium Tc 99m Exametazime
D009593:Nitroimidazoles; D015609:Organotechnetium Compounds; D010091:Oximes; C082027:BMS 181321; C088579:6-methyl propyleneamine oxime; D019690:Technetium Tc 99m Exametazime