Scintigraphic evaluation of myocardial uptake of thallium 201 and technetium 99m pyrophosphate utilizing a rat model of chronic doxorubicin cardiotoxicity.
To evaluate the usefulness of myocardial scintigraphy as a monitoring tool for chronic doxorubicin (DXR) cardiotoxicity, a rat model was used to investigate the relationship between the myocardial uptake of thallium 201 (Tl) or rechnetium 99m pyrophosphate (99mTc-PPi) and histological changes of the heart. Although there was no significant difference in myocardial Tl uptake between control and DXR-treated rats at an early phase after Tl injection, late-phase Tl uptake was significantly higher in the DXR-treated rats than in the control rats, indicating a slow wash-out of Tl from the myocardium. The wash-out rate calculated from scintigraphic examination of DXR-treated rats was significantly decreased with increasing degree of cardiomyopathy. Since the Tl wash-out rate was sharply decreased even in animals with minimal histological changes, it may be a possible monitoring tool for the early detection of chronic DXR cardiotoxicity. On the other hand, myocardial 99mTc-PPi images could be obtained only in rats with severe myocardial changes and hence would not useful for early detection.
Miyagawa
M
M
Department of Radiology, School of Medicine, Ehime University, Japan.
Tanada
S
S
Hamamoto
K
K
D000818:Animals; D009202:Cardiomyopathies / Q000139:chemically induced* / Q000000981:diagnostic imaging; D004317:Doxorubicin / Q000633:toxicity*; D005260:Female; D008991:Monitoring, Physiologic / Q000379:methods; D009206:Myocardium / Q000378:metabolism*; D011877:Radionuclide Imaging; D051381:Rats; D011919:Rats, Inbred Strains; D016698:Technetium Tc 99m Pyrophosphate / Q000493:pharmacokinetics*; D013794:Thallium Radioisotopes / Q000493:pharmacokinetics*
D013794:Thallium Radioisotopes; D016698:Technetium Tc 99m Pyrophosphate; D004317:Doxorubicin