BackgroundClinical assessment of myocardial injury is primarily based on the presence of serum biomarkers and electrocardiogram, with a significant input from perfusion imaging by single photon emission computed tomography (SPECT). Positron emission tomography (PET) is another imaging modality which has the potential to improve diagnostic accuracy by virtue of its high resolution and sensitivity. The objective of this study was to assess isoproteronol‐induced cardiomyopathy by PET using 18F‐fluorodeoxyglucose (FDG) and compare it with conventional SPECT using 99mTc‐Sestamibi (MIBI).MethodsCardiomyopathy was induced in Sprague Dawley rats by injecting high dose of isoproteronol (100 mg/kg, i.p.) on two consecutive days. FDG/PET and MIBI/SPECT were performed before and on the fourth day of isoproteronol administration. FDG (0.1 mCi, 0.2–0.4 mL) and MIBI (2 mCi, 0.5–1 mL) were injected via the tail vein and the images were acquired 1 h post‐injection. The images were analyzed by drawing region of interest (ROI) around heart tissue. Isoproteronol‐induced myocardial injury was verified at necropsy by tissue staining with tetrazolium chloride (TTC) and plasma cardiac troponin.ResultsIsoproteronol administration resulted in a significant increase in circulating troponin I (p < 0.05) as compared to the basal levels. FDG/PET images showed detectable alterations in cardiac accumulation of FDG and ROI analysis revealed a 75% drop of myocardial FDG uptake after isoproteronol treatment. The uptake of MIBI decreased by 45%, but the images did not show any discernible visual change in perfusion. At necropsy, TTC staining showed remarkable changes in all isoproteronol ‐treated hearts.ConclusionThe results suggest that high‐dose isoproteronol significantly impacts cardiac glucose metabolism without commensurate change in myocardial perfusion. PET imaging of glucose metabolism can be employed as a diagnostic criterion in myocardial injury.Support or Funding InformationFunding: Sandra K and David L Gilliland Chair in Nuclear Pharmacy