18F-FDG Positron Emission Tomography in Myocardial Viability Assessment: Oral Glucose and Intravenous Insulin Loading Protocol vs Fasting Status Protocol

Abstract

Background: Determination of myocardial viability is vital for coronary revascularization in patients with ischemic cardiomyopathy (ICM). To select the appropriate strategies for ICM screening, the present study compared the image quality, viability extent, and dyssynchrony of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) myocardial viability imaging in patients with ICM using an oral glucose and intravenous insulin loading (G/I) protocol with a convenient fasting status (FAST). Methods: ¹⁸F-FDG PET metabolic imaging was conducted using the G/I and FAST protocols on different days and ^99mTc-methoxyisobutylisonitrile (MIBI) perfusion imaging in all patients (N = 44). Fluorodeoxyglucose (FDG) image quality was assessed using a 5-point scoring system. The semiquantitative analysis included SUVmean of blood pool (SUVmeanBlood), SUVmax of the whole left ventricular muscle (SUVmaxMyo), and the SUVmeanBlood and SUVmaxMyo ratio (M/B). Furthermore, the quantitative analysis involved comparing the extent of mismatch on polar maps and evaluating left ventricle dyssynchrony between the two groups. The Cohen κ-test was used to investigate positive or negative on left anterior descending (LAD), left circumflex (LCX) or right coronary artery (RCA) between the groups. Results: The imaging quality scores were 4.36 ± 0.94 and 3.55 ± 1.09 using the G/I and FAST protocols, respectively (p < 0.001). Significant differences were found in SUVmeanBlood, SUVmaxMyo, and M/B between the two groups (p < 0.001, 0.007, and <0.001, respectively). G/I and FAST protocols indicated good agreement for positive and negative findings in the LAD, LCX, and RCA (κ = 0.847, 0.858, and 0.74, respectively). Myocardial viability assessment exhibited equivalence between the two groups (all p > 0.05) within the imaging score ranging from 3 to 5. Furthermore, dyssynchrony assessment of left ventricle exhibited no significant difference between the two groups (all p > 0.05). For the G/I method, insulin consumption (95% confidence interval (CI) 0.03–0.27, p = 0.014) and SUVmaxMyo (95% CI 0.07–0.24, p = 0.0005) were identified as significant predictors for metabolic imaging score (coefficient of determination (R²) = 0.6226). Similarly, for the FAST protocol, SUVmaxMyo (95% CI 0.09–0.29, p = 0.0003) was a significant predictor for metabolic imaging score (coefficient of determination (R²) = 0.6787). Conclusions: Our findings indicate that ¹⁸F-FDG PET in assessing myocardial viability using the FAST protocol could be a time-efficient and safe option for clinical personalized practice. Clinical Trial Registration: Chinese Clinical Trial Registry (ChiCTR2400083975).