¹⁸F-FDG PET in Myocardial Viability Assessment: A Practical and Time-Efficient Protocol

Area of Science:

• Nuclear Medicine
• Cardiology
• Diabetology

Background:

• Myocardial viability assessment using 18F-FDG PET is crucial for patients with ischemic cardiomyopathy (ICM).
• Optimal cardiac 18F-FDG uptake requires a specific metabolic preparation period (MPP) involving glucose loading and insulin administration.
• Traditional oral glucose loading protocols can be time-consuming and may yield variable results, particularly in diabetic patients.

Purpose of the Study:

• To evaluate a practical and time-efficient protocol using intravenous glucose loading and insulin injection before 18F-FDG administration.
• To assess the impact of this protocol on cardiac 18F-FDG uptake and image quality in ICM patients, with and without type 2 diabetes mellitus.
• To compare the MPP of the intravenous protocol with traditional oral glucose loading methods.

Main Methods:

• Fifty-nine consecutive ICM patients underwent rest 99mTc-tetrofosmin SPECT/CT and 18F-FDG PET/CT for myocardial viability evaluation.
• Intravenous infusion of 12.5 or 25 g of 50% dextrose followed by insulin injection was used to determine MPP.
• Cardiac 18F-FDG image quality was scored by two independent observers using a 5-point scale; a reference group used oral glucose loading.

Main Results:

• The intravenous protocol resulted in good-to-excellent 18F-FDG image quality in 95% of patients (42% excellent, 36% very good, 17% good).
• Overall image quality scores were significantly higher in nondiabetic patients compared to diabetic patients (4.71 vs. 3.88, P < 0.0001).
• The average MPP was significantly reduced by 61% with the intravenous protocol (51 min) compared to oral loading (132 min; P < 0.0001).

Conclusions:

• The proposed intravenous glucose loading and insulin administration protocol is practical and time-efficient for 18F-FDG PET myocardial viability imaging.
• This protocol significantly shortens the MPP by 61% compared to oral glucose challenges.
• The method affords good-to-excellent image quality in the majority of ICM patients, facilitating effective myocardial viability assessment.