Simultaneous determination of dynamic cardiac metabolism and function using PET/MRI

Area of Science:

• Cardiovascular Imaging
• Cardiac Metabolism
• Preclinical Models

Background:

• Cardiac metabolic alterations precede functional decline in heart disease.
• Current clinical practice rarely assesses cardiac metabolism and function concurrently.
• Understanding this relationship is crucial for early disease detection.

Purpose of the Study:

• To develop a combined cardiac positron emission tomography/magnetic resonance (PET/MR) stress test.
• To evaluate the dynamic interplay between cardiac contractile function and metabolism.
• To utilize a preclinical model for assessing this novel technique.

Main Methods:

• Healthy pigs underwent anesthesia and mechanical ventilation.
• Continuous intravenous infusion of 18F-fluorodeoxyglucose (18F-FDG) was administered.
• A cardiac PET/MR stress test was performed under normoxic and hypoxic conditions using an integrated 3T scanner.

Main Results:

• Hypoxic stress significantly increased heart rate, cardiac output, left ventricular ejection fraction (EF), and peak torsion.
• Hypoxia led to decreased arterial oxygen saturation (SpO2) and altered left ventricular volumes.
• Enhanced left ventricular systolic function correlated with increased myocardial 18F-FDG uptake (Ki) during hypoxic stress.

Conclusions:

• The developed PET/MR stress test effectively captures dynamic changes in cardiac metabolism and function.
• This technique holds promise for assessing subtle functional and metabolic abnormalities in human cardiac disease.
• Further evaluation in human subjects is warranted to validate its clinical utility.