Compartment model for measuring myocardial oxygen consumption using [1-11C]acetate

Area of Science:

• Cardiovascular Imaging
• Nuclear Medicine
• Physiology

Background:

• [1-11C]acetate is a validated PET tracer for myocardial oxygen consumption (MVO2).
• Current fitting methods provide only estimates of MVO2.
• A need exists for a more direct MVO2 estimation method.

Purpose of the Study:

• To develop and validate a simple tracer kinetic model for in vivo estimation of regional MVO2 using [1-11C]acetate.
• To assess the model's performance across a range of physiological conditions.

Main Methods:

• [1-11C]acetate PET imaging was performed in 12 anesthetized dogs (27 experiments).
• Measurements were taken under baseline, ischemia, and pharmacologically induced changes in myocardial blood flow (MBF) and MVO2.
• MVO2 was estimated using the developed PET model and compared with Fick method calculations and microsphere-derived MBF.

Main Results:

• The proposed kinetic model demonstrated excellent fit across all study conditions (R² = 0.985 ± 0.026).
• Estimated MVO2 showed a strong linear correlation with measured MVO2 (r = 0.92).

Conclusions:

• A simple tracer kinetic model enables reliable assessment of myocardial oxygen consumption (MVO2) using [1-11C]acetate PET.
• This validated model can be used to assess MVO2 over a wide physiological range.