Non-calcified active atherosclerosis plaque detection with 18F-NaF and 18F-FDG PET/CT dynamic imaging

Area of Science:

• Cardiovascular Imaging
• Nuclear Medicine
• Radiology

Background:

• Arterial inflammation is a key indicator of atheromatous plaque vulnerability, potentially leading to heart attack or stroke.
• Predicting plaque vulnerability remains challenging with current diagnostic methods.

Purpose of the Study:

• To evaluate the uptake of 18F-sodium fluoride (18F-NaF) and 18F-fluorodeoxyglucose (18F-FDG) in arterial plaques.
• To correlate radiotracer uptake with plaque density on computed tomography (CT) images.

Main Methods:

• 18 elderly volunteers underwent CT and positron emission tomography (PET) scans using 18F-NaF and 18F-FDG.
• Analysis of 1338 arterial segments (766 non-calcified, 572 calcified) to compare radiotracer uptake (SUV) and plaque density.
• Clustering of non-calcified plaque segments based on CT density to identify distinct plaque types.

Main Results:

• Significant differences in 18F-NaF and 18F-FDG uptake were observed between non-calcified and calcified arterial segments.
• Two distinct clusters of non-calcified plaques (C1 and C2) showed statistically different densities and radiotracer uptakes.
• 18F-NaF PET identified plaques not visible on CT, with high 18F-FDG uptake compared to normal artery walls.

Conclusions:

• Metabolically active arterial plaques associated with inflammation can occur in the absence of calcification.
• Plaque density on CT imaging may serve as an indicator for identifying active, vulnerable plaques.
• Combined CT and PET imaging with 18F-NaF and 18F-FDG offers potential for improved assessment of plaque vulnerability.